Bump underscore from 1.12.0 to 1.13.6 in /frontend

[dependabot[bot]]

Bumps underscore from 1.12.0 to 1.13.6.

Commits

• bd2d35c Merge remote-tracking branch 'upstream/master'
• 2e7c0f2 Update generated files, tag 1.13.6 release
• 732cafe Underscore 1.13.6
• e8f86fb Add changelog entry for versioin 1.13.6
• 43e827a Bump the version to 1.13.6 (hotfix)
• 1c1d1a2 Remove patch-package postinstall script
• 4eb6894 Merge pull request #2974 from paulsmithkc/patch-1
• 2edcdc1 Hostfix for broken builds
• 66ee70d Verify that production and doc builds still work in CI
• 68e5eb6 Update generated sources, tag 1.13.5 release
• Additional commits viewable in compare view

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