refactor bria pipeline tests to the new mixin structure

[akshan-main]

What does this PR do?

Refactors the Bria pipeline tests to the new mixin structure from #14113: a BriaPipelineTesterConfig plus TestBriaPipeline(PipelineTesterMixin) and TestBriaPipelineMemory(MemoryTesterMixin), with the slow class ported to pytest as TestBriaPipelineSlow.

Existing coverage is kept: test_bria_different_prompts and both output-shape tests, with dummy inputs switched to output_type="pt" and a fresh CPU slice in test_inference. The old silent test_encode_prompt_works_in_isolation override is now an explicit skip with the diagnosed reason (BriaPipeline.__init__ dereferences the vae config, so it cannot be built with text-only components). The float16/dtype overrides are dropped in favor of the framework versions, which pass unmodified.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline?
• Did you read our philosophy doc (important for complex PRs)?
• Was this discussed/approved via a GitHub issue or the forum? Discussed on Slack with @sayakpaul
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?

Who can review?

@sayakpaul

[sayakpaul]

/diffusers-bot pytest tests/pipelines/bria/test_pipeline_bria.py

[github-actions]

⚠️ pytest tests/pipelines/bria/test_pipeline_bria.py was cancelled on GPU — view logs.

[sayakpaul]

@akshan-main additionally, let's also add the LoraTesterMixin similar to:

diffusers/tests/pipelines/flux/test_pipeline_flux.py

Line 370 in 2f7e015

class TestFluxPipelineLoRA(FluxPipelineTesterConfig, LoraTesterMixin):

[sayakpaul]

/diffusers-bot pytest tests/pipelines/bria/test_pipeline_bria.py

[github-actions]

✅ pytest tests/pipelines/bria/test_pipeline_bria.py passed on GPU — view logs.

[akshan-main]

Added. Note BriaPipeline doesn't subclass LoraBaseMixin, so the class skips through the mixin's setup gate for now.

[sayakpaul]

Sorry. I should have been clear here. If the corresponding pipeline doesn't already have a separate LoRA tester under tests/lora, then no need to add. This means we can remove the LoRA bits you just added. I am sorry for the confusion.

[github-actions]

Hi @akshan-main, thanks for the PR! It does not appear to link an issue it fixes. If this PR addresses an existing issue, please add a closing keyword (e.g. Fixes #1234) to the PR description so the issue is linked. See the contribution guide for more details. If this PR intentionally does not fix a tracked issue, a maintainer can add the no-issue-needed label to silence this reminder.

[akshan-main]

No worries, removed.