_validateSpecial in bson_validate.cpp:552-565 validates BSONColumn content at all modes including kDefault, throwing NonConformantBSON.Column content validation should only run at Extended/Full (for db.validate()), not kDefault. kDefault should treat BinData(7) as opaque binary like other subtypes.

SERVER-128347 added non-bypassable column validation in checkValidation at the timeseries write path, so removing it from kDefault is safe.

Changes:
  - Gate _doValidateColumn on non-kDefault in _validateSpecial
  - Use uassertStatusOK instead of uassert(NonConformantBSON) to preserve real error codes
  - Update bson_validate_test.cpp, bson_validate.h
  - Update jstests/noPassthrough/validate_js_generated_bson.js, jstests/disk/validate_bson_inconsistency.js,
  expression_javascript_test.cpp

for more context see https://github.com/10gen/mongo/pull/57237/changes#r3513777467