[7.x] [jest/ci] remove max-old-space-size override to use 4gb default (#91020)

[kibanamachine]

Backports the following commits to 7.x:

• [jest/ci] remove max-old-space-size override to use 4gb default ([jest/ci] remove max-old-space-size override to use 4gb default #91020)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: e783174

Metrics [docs]

✅ unchanged

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