[BUG] Handle get key operation when no tag has been set (#3256)

* Bug-fix

Signed-off-by: Patrick St-Louis <43082425+PatStLouis@users.noreply.github.com>

* Update in_memory.py

Signed-off-by: Patrick St-Louis <43082425+PatStLouis@users.noreply.github.com>

* linting

Signed-off-by: PatStLouis <patrick.st-louis@opsecid.ca>

* apply better suggestion

Signed-off-by: PatStLouis <patrick.st-louis@opsecid.ca>

* set empty tags object instead of none for consistency

Signed-off-by: PatStLouis <patrick.st-louis@opsecid.ca>

* remove unnecessary change in the in memory wallet

Signed-off-by: PatStLouis <patrick.st-louis@opsecid.ca>

---------

Signed-off-by: Patrick St-Louis <43082425+PatStLouis@users.noreply.github.com>
Signed-off-by: PatStLouis <patrick.st-louis@opsecid.ca>

aries_cloudagent/wallet/askar.py

@@ -97,7 +97,7 @@ async def create_key(
         if kid:
             tags = {"kid": kid}
         else:
-            tags = None
+            tags = {}
 
         try:
             keypair = _create_keypair(key_type, seed)
@@ -192,8 +192,10 @@ async def get_signing_key(self, verkey: str) -> KeyInfo:
         if not key:
             raise WalletNotFoundError("Unknown key: {}".format(verkey))
         metadata = json.loads(key.metadata or "{}")
+
+        kid = key.tags.get("kid")
+
         # FIXME implement key types
-        kid = key.tags["kid"] if "kid" in key.tags else None
         return KeyInfo(verkey=verkey, metadata=metadata, key_type=ED25519, kid=kid)
 
     async def replace_signing_key_metadata(self, verkey: str, metadata: dict):