[xattr] Able to create xattr key with semi-colon character

Build: 7.0.0-4907

Scenario:

• Single node cluster, couchbase bucket (replica=0)
• Insert empty document
• Add xattr into the doc with key "test;test"

Observation:

xattr key "test;test" gets inserted without any exception.

Expected behavior:

As per the mobile-convergence kv_spec doc: https://docs.google.com/document/d/18UVa5j8KyufnLLy29VObbWRtoBn9vs8pcxttuMt6rz8/edit#, xattr key containing ";" should be treated as invalid xattr-key.

QE testrunner test (py-sdk):

subdoc.subdoc_xattr_sdk.SubdocXattrSdkTest:

  test_key_inside_characters_negative

Code to reproduce in TAF (Java sdk):

client = SDKClient([self.cluster.master], self.bucket_util.buckets[0])

client.crud("create", "key_1", {})

client.crud("insert", "key_1", ["test;test", "x_val"], create_path=True, xattr=True)

client.close()