Bump extension version

[award999]

Description

• Bump the extension version so targeting next release version, adding -dev to distinguish
• Decrement pre-release minor version since manifest will now have the next, not current version
• Allow -dev in vsix file name when downloading vsix for tests
• When downloading VSIX, add the actual file name to GITHUB_ENV, without renaming
• Determine version from the VSIX filename or fallback to the package.json version
• Realized that in CI the VSIX was NOT being used for linux runs so fixed this and:
  • Moved wait for index logic into bundled extension because otherwise GLSP V2.3 - VS-Code Integration - Unknown parameter structure auto eclipse-glsp/glsp#1480 occurred
  • Added console logging in .vscode-test.js so we could see whether extension was being used and which extensionDevelopmentPath
• skipExtensionDependencies in CI
• The RUNNING_IN_CI does not work so introduce new logic to check if source is being run as part of the test CLI instead
  • Make "VSCODE_TEST" env var longer so harder to accidentally set

Issue: N/A

Tasks

• Required tests have been written
• Documentation has been updated
• Added an entry to CHANGELOG.md if applicable

[award999]

The full nightly run also passed on my fork's action https://github.com/award999/vscode-swift/actions/runs/16681615407