release-26.1: builtins: call Parse instead of ParseOne in crdb_internal.inject_hint

[blathers-crl]

Backport 1/1 commits from #159321 on behalf of @michae2.

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This changes an internal error to a regular error with a pgcode.

Fixes: #158658
Fixes: #159232

Release note: None

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Release justification: fix for a bug causing frequent test failures.

[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that the change does not break backwards compatibility and otherwise complies with the backport policy. Include a brief release justification in the PR description explaining why the backport is appropriate. All backports must be reviewed by the TL for the owning area. While the stricter LTS policy does not yet apply, please exercise judgment and consider gating non-critical changes behind a disabled-by-default feature flag when appropriate.

[cockroach-teamcity]

This change is