Fix TypeError in EE BlobOverflowMenu when Apollo query errors

What does this MR do and why?

this MR fixes two issues that generates sentry error in ee/app/assets/javascripts/repository/components/header_area/blob_overflow_menu.vue:

1. add missing i18n option that fixes TypeError: Cannot read properties of undefined (reading 'fetchError')
2. add fallback value for the same query's update() hook

References

• Sentry issue: https://new-sentry.gitlab.net/organizations/gitlab/issues/3882971/
• GitLab issue: https://gitlab.com/gitlab-org/gitlab/-/work_items/625055

Screenshots or screen recordings

No UI change — this only affects the error alert message text when the GraphQL query fails.

Before	After
TypeError: Cannot read properties of undefined (reading 'fetchError') thrown, no alert shown	Alert shown with correct message: "An error occurred while fetching lock information, please try again."

How to set up and validate locally

1. Navigate to any blob page on a GitLab EE instance (e.g. https://gitlab.com/git-scm/git/-/blob/main/blob.h)
2. Simulate a GraphQL failure for getProjectInfoEE (e.g. via network throttling or a mock)
3. Before fix: a JS TypeError is thrown in the console, no alert is shown
4. After fix: an alert banner appears with the fetch error message
5. Run the unit tests:

yarn jest ee/spec/frontend/repository/components/header_area/blob_overflow_menu_spec.js

MR acceptance checklist

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