search-in-workspace: add noselect to line result nodes

[Archie27376]

What it does

Fixes: #10362

The commit adds noselect to the line result nodes so their inner text is
not selectable, aligning with the rest of the framework and vscode.

How to test

• open search-in-workspace widget
• perform a search that yields results
• individual line results should not have their inner content selectable

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

I confirmed that t works well 👍

• the inner content for search-in-workspace line result nodes are no longer selectable
• the changes work well when searching in a multi-root workspace
• there is no regression when the node itself is selected

[alvsan09]

I can also confirm that the solution works well and no regressions were detected 👍
thanks @Archie27376 !