Improve cypress integration test performance and fix flaky tests

[lresende]

What changes were proposed in this pull request?

Improve cypress integration test performance and fix flaky tests

Fix flaky integration tests by replacing ~30 cy.wait() calls across all test files with proper Cypress retry-able assertions. Key changes:

• Fix openFileAndCheckContent race condition using .should('contain.text')
• Add editor/launcher visibility waits in openHelloWorld and resetJupyterLab
• Replace savePipeline wait with dirty-state check
• Scope uncaught exception handler to known benign errors
• Increase defaultCommandTimeout from 8s to 10s

Fixes #3301

How was this pull request tested?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3350   +/-   ##
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  Coverage        ?   84.16%           
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  Files           ?      157           
  Lines           ?    19067           
  Branches        ?      504           
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  Hits            ?    16048           
  Misses          ?     2827           
  Partials        ?      192           

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