chore: Downgrade auto-indexing scip-go SHA and pin version in CI

[varungandhi-src]

Partly reverts https://github.com/sourcegraph/sourcegraph/pull/63801
due to sourcegraph/scip-go#119 which is blocked
on upstream golang/go#68877

Test plan

n/a - covered by existing tests

[keegancsmith]

FYI I added the backport label since on the 5.6.x branch we are getting scip-go failures. I think this will resolve it.

[sourcegraph-release-bot]

The backport to 5.6.x failed at https://github.com/sourcegraph/sourcegraph/actions/runs/10452871752:

The process '/usr/bin/git' failed with exit code 1

To backport this PR manually, you can either:

Via the sg tool

Use the sg backport command to backport your commit to the release branch.

sg backport -r 5.6.x -p 64477

Via your terminal

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-5.6.x 5.6.x
# Navigate to the new working tree
cd .worktrees/backport-5.6.x
# Create a new branch
git switch --create backport-64477-to-5.6.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 badd28ec24af693cdb4203fbc70d166069fa765b
# Push it to GitHub
git push --set-upstream origin backport-64477-to-5.6.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-5.6.x

If you encouter conflict, first resolve the conflict and stage all files, then run the commands below:

git cherry-pick --continue
# Push it to GitHub
git push --set-upstream origin backport-64477-to-5.6.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-5.6.x

• Follow above instructions to backport the commit.
• Create a pull request where the base branch is 5.6.x and the compare/head branch is backport-64477-to-5.6.x., click here to create the pull request.

Once the pull request has been created, please ensure the following:

• Make sure to tag @sourcegraph/release in the pull request description.

• kindly remove the release-blocker from this pull request.

[keegancsmith]

I'll manually cherry-pick with only the scip-go workflow action change. @varungandhi-src for the patch release should we be updating the scip hashes to be using in internal/codeintel/autoindexing/internal/inference/libs/indexes.go?

[varungandhi-src]

@keegancsmith https://github.com/sourcegraph/sourcegraph/pull/63801 was not cherry-picked to the release branch, so this patch also shouldn't need to be cherry-picked.

Conversely, if one is present, then the other should cleanly cherry-pick on top without conflicts.

[keegancsmith]

ok, but I should still go ahead and cherry-pick in the github action changes I assume? They look related.

[keegancsmith]

@varungandhi-src partial cherry-pick done here, you can comment on that PR to continue discussion :) https://github.com/sourcegraph/sourcegraph/pull/64535