fix: Support Remark Line Breaks in Agent Response

[bytrangle]

Describe Your Changes

There have been various reports of new lines not being rendered in model response. I think this issue comes from the RenderMarkdown component. remark-breaks, the Remark plugin that supports line breaks is only added when prop isUser is true. isUser is only passed as true for user message. For model response, this prop is not passed to RenderMarkdown so isUser is undefined, thus preventing remark-breaks from working.

Fixes Issues

• Closes bug: Chat message view sometimes drops newline characters #6749

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed

[Copilot]

Pull Request Overview

This PR modifies the RenderMarkdown component to always use remarkBreaks plugin for all markdown content (both user messages and model responses), removing the conditional logic that previously applied it only to user messages. This ensures consistent line break handling across all message types.

Key Changes

• Applied remarkBreaks plugin unconditionally to all markdown content regardless of isUser prop value
• Simplified the remarkPlugins memoization by removing the dependency on isUser
• Added comprehensive test coverage for line break preservation in various scenarios

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
web-app/src/containers/RenderMarkdown.tsx	Removed conditional remarkBreaks application, now always included in the plugin array
web-app/src/containers/tests/RenderMarkdown.test.tsx	Added new test file with 4 test cases covering line break handling for model responses, user messages, different line endings, and empty lines

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[Vanalite]

This looks good, pls help to fix the tests and resolve latest conflicts, then we can have your PR merged. Thanks @bytrangle

[louis-jan]

LGTM

[Copilot]

Pull Request Overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

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