Add TestBitFlipCorruptObjectDeletion to exercise the decoder error path
for KEP-3926 using Secrets (protobuf encoding). Unlike the existing
TestAllowUnsafeMalformedObjectDeletionFeature which tests transformer
errors (wrong encryption key), this test uses identity encryption and
corrupts stored bytes directly in etcd, triggering "undecodable" errors
at the protobuf decoder layer.
The informer is given an extended timeout (2 minutes) after deletion
to recover from the exponential backoff accumulated during the
corruption window. The reflector's backoff caps at [30s, 60s) with
jitter, so 2 minutes provides sufficient leeway.
The gate=false subtest is skipped because writing corrupt bytes directly
to etcd emits a watch event that the cacher cannot decode, breaking its
watch. Without the feature gate, the subsequent re-list aborts on the
first decode error (abortOnFirstError aggregator), so the cacher never
recovers and GET requests hang. This differs from the encryption-config
swap tests where no etcd data changes and no watch event is emitted.
This is a known issue to be addressed separately.
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