[Fix] Avoid caching failed image inflation

[NachoSoto]

Summary

• mark failed bitmap-context inflation and image-processing results as non-cacheable while still returning the original image as a safe fallback
• keep CacheRenderer from storing those fallback results
• preserve cacheability metadata through renderer conversions without changing MulticastedRenderer lifecycle behavior
• add regressions covering failure, recovery, and the subsequent valid cache hit through both .inflatedWithScale(...).withCache(...) and .processedWithScale(...).withCache(...)

Root cause

The fallback added in #74 returned the original image as an ordinary successful render result. CacheRenderer therefore stored that full-size or unprocessed image under the requested output key. A transient bitmap allocation or output-image creation failure could consequently poison future requests instead of allowing them to retry after memory pressure subsided.

This follows up on the resolved review thread in #74 and the processing review thread in this PR.

Validation

• xcodebuild test -scheme AsyncImageView -destination 'platform=iOS Simulator,id=E256AEBA-8DCF-4F9C-B2CD-0722FADA3C2F' CODE_SIGNING_ALLOWED=NO — 62 tests passed
• swiftlint --config .swiftlint.yml --strict — 0 violations

[chatgpt-codex-connector]

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