fix: readonly shares should not seem editable

fixes #2769

Signed-off-by: Max <[email protected]>

Author: max-nextcloud

css/prosemirror.scss

@@ -26,7 +26,10 @@ div.ProseMirror {
 		-webkit-user-select: text;
 		user-select: text;
 		font-size: 14px;
+	}
 
+	&[contenteditable=true],
+	[contenteditable=true] {
 		* {
 			-webkit-user-modify: read-write-plaintext-only;
 		}