Remove non-functioning code from invalid credentials Theia case

[lauren-li]

Proposed changes

This PR removes a non-functioning promptCredentials call in the "Invalid Credentials" case for Theia. See comment #1365 (comment) for more details.

Release Notes

Milestone: 1.17.0

Changelog: (No user-facing change.) Remove non-functional code from invalid credentials Theia case.

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Further comments

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[crawr]

Thanks @lauren-li

I agree with removing this prompt until the caching issue in Theia is solved.