[AnnotationsToAttributes] Convert external @depends ClassName::method to #[DependsExternal]

[TomasVotruba]

Fixes rectorphp/rector#9539

When a @depends annotation references a method on another test class (@depends OtherTest::testMethod), DependsAnnotationWithValueToAttributeRector left it untouched. PHPUnit expresses a cross-class dependency with a dedicated attribute that takes the class and method as two arguments:

-    /**
-     * @depends \Some\OtherTest::testIsImmutable
-     */
+    #[\PHPUnit\Framework\Attributes\DependsExternal(\Some\OtherTest::class, 'testIsImmutable')]
     public function testIsImmutable(): void

Previously this case fell through all resolvers and produced no change (or, as reported, a malformed single-argument #[Depends(Other::testIsImmutable)]).

What changed

• Added a resolveDependsExternalClassMethod() branch that recognises ClassName::method (skipping ::class, already handled by DependsOnClass, and clone …, handled by DependsUsingDeepClone) and emits #[DependsExternal(ClassName::class, 'method')].
• Refactored the resolver to return [attributeClass, items[]] so attributes can carry more than one argument (the existing single-argument cases keep their behaviour).

Tests

• New fixture Fixture/depends_external.php.inc.
• Full rules-tests/AnnotationsToAttributes suite is green; ECS, PHPStan and Rector pass on the changed rule.

Scope note: the deep-clone external variant (@depends clone OtherTest::method → DependsExternalUsingDeepClone) is intentionally left out of scope and explicitly skipped, so its current behaviour is unchanged.

[TomasVotruba]

LGTM 👍