feat(webui): add reset column sizes button to grid toolbar, Fixes #1308

[mohamadyasser118]

Description

Fixes #1308

useGridState already exposes resetColumnSizes() but it was never
connected to the UI.

I Added optional onResetColumns prop to GridToolbar so only grids that use useGridState show the button,
And Wired resetColumnSizes through SourcesGridToolbar into SourcesGrid.

AI & Automation Policy

• I am the human author and take full personal responsibility for every change in this PR.
• No AI or automated generative tool was used in any part of this PR OR I have disclosed all tool(s) below.
  Drafted with the assistance of Claude Sonned 4.6

Checklist

• Code compiles and existing tests pass locally.
• New or updated tests are included where applicable.
• Documentation is updated where applicable.

[Mazen050]

Hello @mohamadyasser118, similar to last time. the connection string column doesn't reset size (doesn't expand/contract to default size). Although every other column does.

[mohamadyasser118]

Hello @mohamadyasser118, similar to last time. the connection string column doesn't reset size (doesn't expand/contract to default size). Although every other column does.

Yes I know, This can be avoided when the glitching problem is fixed, However as this problem still exist, it will need another refactor after fixing it.

[mohamadyasser118]

As I mentioned in the previous PR, ConnetionString has a different behavior because of using flex rather than width

[mohamadyasser118]

@pashagolub
Hello, I made edits on SourcesGrid.tsx after your PR (replacing onColumnResizewith onColumnWidthChange)
also the problem of Connection String column has been fixed in #1324