fix(neotest): prevent running multiple tests when running a single test with cargo-nextest

[lpiepiora]

Fixes #618.

I have tested this manually:

1. Uninstalled the cargo-nextest

2. Installed 0.9.80 (which does not support the flag)

3. Installed the correct version

I have tested the tests are now not executed if not needed (for example when running test_function_1:

    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.01s
────────────
 Nextest run ID a08a7486-cd35-4d6d-b0ce-4cde971c1b3c with nextest profile: default
    Starting 1 test across 1 binary (1 test skipped)
        PASS [   0.017s] rust-test::bin/rust-test test::test_function_1
────────────
     Summary [   0.019s] 1 test run: 1 passed, 1 skipped

[github-actions]

Review Checklist

Does this PR follow the Contribution Guidelines? Following is a partial checklist:

Proper conventional commit scoping:

• For example, fix(lsp): some lsp-related bugfix

• Pull request title has the appropriate conventional commit prefix.

If applicable:

• Tested
  • Tests have been added.
  • Tested manually (Steps to reproduce in PR description).
• Updated documentation.

[mrcjkb]

Thanks 🙏