fix: guard against null ITextEditor document provider - #585

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@1bd1e32a3bdc45362d1e726936510720a7c30a57, actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683, actions/checkout@v4, actions/setup-java@7a6d8a8234af8eb26422e24e3006232cccaa061b, actions/upload-artifact@v4, s4u/maven-settings-action@64e42c454dbd42ef6370ac8539685755aedd205b, stCarolas/setup-maven@d6af6abeda15e98926a57b5aa970a96bb37f97d1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

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