Create RefSearchForm component for repository graph

What does this MR do and why?

• introduce a dropdown component for selecting the ref of the repository graph
• rerender the graph only after submitting the chosen SHA and type of graph

References

• Form field causes unexpected change
• design proposal

Screenshots or screen recordings

Before	After
Screen_Recording_2025-09-04_at_18.15.53	Screen_Recording_2025-09-04_at_18.06.49

How to set up and validate locally

⚠️ the commit graph doesn't load for me locally because it is missing a dependency called eve

1. Add let eve = {}; at the top of the node_modules/raphael/raphael.js file
2. Delete the tmp/cache folder and run yarn cache clean to clear the cache
3. Restart GDK
4. Navigate to http://127.0.0.1:3000/<project>/-/network/master?ref_type=heads
5. Choose the display mode of the graph (full history or up to a revision). Paste a commit SHA and click Search icon button.
6. Verify that the graph rerenders only after clicking search.
7. Make sure the commit you chosen in the Display up to revision mode is the first one show in the graph.

MR acceptance checklist

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Related to #511688