Replace unnecessary search areas with just branch search

[gtsiolis]

trafficstars

Searching through branches can be easier to understand and use.

Cc @Palanikannan1437 @henit-chobisa

Cc @mads-hartmann because we recently chatted about this

[mads-hartmann]

@gtsiolis I opened https://github.com/gitpod-samples/Gitpod-Raycast-Extension/issues/88 as I do think it's useful to be able to filter on issues, PRs, etc. but with https://github.com/gitpod-samples/Gitpod-Raycast-Extension/issues/88 we could have Branches be the default item in the dropdown and that would fix this issue I thin.