minor #3108 [CI] Remove duplicated matrix entry for Symfony version in unit-tests.yaml (Kocal)

This PR was merged into the 2.x branch.

Discussion
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[CI] Remove duplicated matrix entry for Symfony version in unit-tests.yaml

| Q              | A
| -------------- | ---
| Bug fix?       | yes
| New feature?   | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations?  | no <!-- if yes, also update UPGRADE-*.md and src/**/CHANGELOG.md -->
| Documentation? | no <!-- required for new features, or documentation updates -->
| Issues         | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License        | MIT

<!--
Replace this notice by a description of your feature/bugfix.
This will help reviewers and should be a good start for the documentation.

Additionally (see https://symfony.com/releases):
 - Always add tests and ensure they pass.
 - For new features, provide some code snippets to help understand usage.
 - Features and deprecations must be submitted against branch main.
 - Update/add documentation as required (we can help!)
 - Changelog entry should follow https://symfony.com/doc/current/contributing/code/conventions.html#writing-a-changelog-entry
 - Never break backward compatibility (see https://symfony.com/bc).
-->

Commits
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9c96e1b [CI] Remove duplicated matrix entry for Symfony version in unit-tests.yaml

Author: Kocal

.github/workflows/unit-tests.yaml

@@ -47,8 +47,6 @@ jobs:
                         symfony-version: '6.4.*'
                         os: 'windows-latest'
                     # Explicit Symfony versions
-                    -  php-version: '8.1'
-                       symfony-version: '6.4.*'
                     -  php-version: '8.2'
                        symfony-version: '7.4.x-dev' # TODO: change to '7.4' when Symfony 7.4 is released
                     -  php-version: '8.5'