Update Block Patterns Controller PHPUnit tests

[Mamaduka]

What?

PR updates Block Patterns Controller tests to match the core and reduce noise when running them.

Why?

Use @doesNotPerformAssertions instead of $this->markTestIncomplete(); when controlled doesn't implement the method.

Testing Instructions

CI is green.

npm run test:unit:php -- --filter Gutenberg_REST_Block_Patterns_Controller_6_2_Test