Prebid 11: toss mediatype mismatch bids; avoid mediaType mismatch rejects when adapter omits mediaType

[patmmccann]

redoes #14468 on the 11 branch as review indicated it might be breaking

Motivation

• Prevent adapters that intentionally omit mediaType from having their bids rejected due to createBid() defaulting mediaType to 'banner'.
• Backport the media-type enforcement from the referenced change to the 11 branch while addressing the review comment that the guard should be skipped when the adapter did not explicitly set mediaType.

Description

• Add an explicit responseMediaType parameter propagated via addBidWithCode() into isValid() so the code can distinguish an adapter-omitted mediaType from an explicit one.
• Preserve whether the adapter response contained mediaType by passing null when mediaType is not an own property of the adapter response; only enforce the ad-unit vs response media-type guard when responseMediaType is non-null.
• Update isValid() signature to accept {responseMediaType} and run the media-type compatibility check against the ad unit only when responseMediaType != null.
• Add unit tests in test/spec/unit/core/bidderFactory_spec.js that cover rejecting explicit mismatches, accepting explicit matches, and skipping the guard when the adapter omitted mediaType.

Testing

• Lint run with npx eslint --cache --cache-strategy content and npx gulp lint --files 'src/adapters/bidderFactory.ts,test/spec/unit/core/bidderFactory_spec.js' completed successfully.
• Unit test run npx gulp test --nolint --file test/spec/unit/core/bidderFactory_spec.js completed successfully (tests passed).
• The changes are limited to src/adapters/bidderFactory.ts and test/spec/unit/core/bidderFactory_spec.js and the updated tests validate the new behavior.

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Codex Task