text: fix stuck selection after clicking a link

[linyisu]

Description

Fixes an issue where dragging the mouse after clicking a link in a TextView causes an unintended text selection.

When a link is clicked, the MouseUp handler calls cx.stop_propagation() before opening the URL. This prevents the window-level TextSelectionController from receiving the event, leaving is_selecting stuck at true. Any subsequent mouse movement is then treated as a drag, highlighting text the user never intended to select.

This PR calls Root::end_text_selection(cx) before stop_propagation() in both link paths:

• Plain inline links — crates/ui/src/text/inline.rs
• Image links — crates/ui/src/text/node.rs

Screenshot

Before

before.mp4

After

after.mp4

How to Test

Open any story that renders a TextView containing a link (e.g. the Markdown story).

Click a link and let the browser open the URL.

Return to the app window and move the mouse without pressing any button.

Checklist

• I have read the CONTRIBUTING document and followed the guidelines.
• Reviewed the changes in this PR and confirmed AI generated code (If any) is accurate.
• Passed cargo run for story tests related to the changes.
• Tested macOS, Windows and Linux platforms performance (if the change is platform-specific)