fix: pin @babel/core dep in test targets

[alharris-at]

Issue #, if available:
aws-amplify/amplify-ui#1242

Description of changes:
pin deps until this issue is resolved upstream.

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[codecov-commenter]

Codecov Report

Merging #377 (7eacc94) into main (9624d5d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #377   +/-   ##
=======================================
  Coverage   89.63%   89.63%           
=======================================
  Files          36       36           
  Lines        1244     1244           
  Branches      278      278           
=======================================
  Hits         1115     1115           
  Misses        126      126           
  Partials        3        3           

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[alharris-at]

It looks like Babel has already fixed upstream. Running canaries now to confirm if this change is needed.

[alharris-at]

Yeah, canary succeeds now with the babel fix. Closing this PR.