Fix nullability of WebView.EditingDelegate

[filipnavara]

Note that both the headers and the documentation are incorrect in this case. All of the WebView.*Delegate objects are documented as non-nullable, but in all cases it's wrong. The binding for the other Delegates allows nulls in Xamarin.

Failure to remove the EditingDelegate reference may result in a crash when the WebView object gets disposed:

16  xamarin_release_managed_ref + 108 (eM Client + 63772) [0x100ecf91c]
  16  -[Xilium_CefGlue_CefWebView release] + 32 (eM Client + 116128) [0x100edc5a0]
  16  xamarin_invoke_objc_method_implementation + 140 (eM Client + 73400) 
[0x100ed1eb8]
  16  -[WebView dealloc] + 112 (WebKitLegacy + 166520) [0x1ccf72a78]
  16  -[WebView(WebPrivate) _close] + 364 (WebKitLegacy + 167048) [0x1ccf72c88]
  16  WebCore::FrameLoader::detachFromParent() + 48 (WebCore + 628864) [0x1d248f880]
  16  WebCore::FrameLoader::closeURL() + 244 (WebCore + 26226672) [0x1d3cf8ff0]
  16  WebEditorClient::clearUndoRedoOperations() + 52 (WebKitLegacy + 102060) 
[0x1ccf62eac]
  16  -[WebView(WebViewEditing) undoManager] + 72 (WebKitLegacy + 153444) 
[0x1ccf6f764]
  16  _CF_forwarding_prep_0 + 96 (CoreFoundation + 408816) [0x1b6993cf0]
  16  ___forwarding___ + 1004 (CoreFoundation + 410012) [0x1b699419c]
  16  objc_opt_respondsToSelector + 48 (libobjc.A.dylib + 185536) [0x1b67944c0]
  7   PAL_DispatchExceptionWrapper + 16 (libcoreclr.dylib + 262040) [0x102db7f98]

[rolfbjarne]

/azp run

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[vs-mobiletools-engineering-service2]

💻 [CI Build] Windows Integration Tests passed 💻

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Hash: 934ca92afb3f780a11e85abefd028c862096e966 [PR build]

[vs-mobiletools-engineering-service2]

✅ API diff for current PR / commit

Legacy Xamarin (No breaking changes)

• iOS (no change detected)
• tvOS (no change detected)
• watchOS (no change detected)
• macOS (no change detected)

NET (empty diffs)

• iOS: (empty diff detected)
• tvOS: (empty diff detected)
• MacCatalyst: (empty diff detected)
• macOS: (empty diff detected)

✅ API diff vs stable

Legacy Xamarin (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• watchOS: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)

.NET (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• MacCatalyst: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)
• Microsoft.iOS vs Microsoft.MacCatalyst: vsdrops gist

Legacy Xamarin (stable) vs .NET

• iOS: vsdrops gist
• tvOS: vsdrops gist
• macOS: vsdrops gist

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

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[vs-mobiletools-engineering-service2]

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• xamarin.ios-16.5.0.135.pkg
• xamarin.mac-9.4.0.135.pkg

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[vs-mobiletools-engineering-service2]

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✅ All tests on macOS M1 - Mac Big Sur (11.5) passed.

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[vs-mobiletools-engineering-service2]

❌ [PR Build] Tests on macOS M1 - Mac Ventura (13.0) failed ❌

Failed tests are:

• monotouch-test

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[vs-mobiletools-engineering-service2]

🚀 [CI Build] Test results 🚀

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✅ All tests passed on VSTS: simulator tests.

🎉 All 227 tests passed 🎉

Tests counts

✅ bcl: All 69 tests passed. Html Report (VSDrops) Download
✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests: All 1 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 7 tests passed. Html Report (VSDrops) Download
✅ framework: All 8 tests passed. Html Report (VSDrops) Download
✅ generator: All 2 tests passed. Html Report (VSDrops) Download
✅ interdependent_binding_projects: All 7 tests passed. Html Report (VSDrops) Download
✅ install_source: All 1 tests passed. Html Report (VSDrops) Download
✅ introspection: All 8 tests passed. Html Report (VSDrops) Download
✅ linker: All 65 tests passed. Html Report (VSDrops) Download
✅ mac_binding_project: All 1 tests passed. Html Report (VSDrops) Download
✅ mmp: All 2 tests passed. Html Report (VSDrops) Download
✅ mononative: All 12 tests passed. Html Report (VSDrops) Download
✅ monotouch: All 27 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ mtouch: All 1 tests passed. Html Report (VSDrops) Download
✅ xammac: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 8 tests passed. Html Report (VSDrops) Download
✅ xtro: All 2 tests passed. Html Report (VSDrops) Download

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Hash: 934ca92afb3f780a11e85abefd028c862096e966 [PR build]