feature #57777 [VarDumper] Add support for FORCE_COLOR environment variable (artshade)

This PR was squashed before being merged into the 7.2 branch.

Discussion
----------

[VarDumper] Add support for `FORCE_COLOR` environment variable

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Issues        |
| License       | MIT

Commits
-------

5b545240c6 [PhpUnitBridge][Console][VarDumper] Add support for `FORCE_COLOR` environment variable

Author: nicolas-grekas

Diff for: DeprecationErrorHandler.php

@@ -411,6 +411,11 @@ private static function hasColorSupport(): bool
             return false;
         }
 
+        // Follow https://force-color.org/
+        if ('' !== (($_SERVER['FORCE_COLOR'] ?? getenv('FORCE_COLOR'))[0] ?? '')) {
+            return true;
+        }
+
         // Detect msysgit/mingw and assume this is a tty because detection
         // does not work correctly, see https://github.com/composer/composer/issues/9690
         if (!@stream_isatty(\STDOUT) && !\in_array(strtoupper((string) getenv('MSYSTEM')), ['MINGW32', 'MINGW64'], true)) {