Remove time.Sleep calls from WACI BDD tests once listener handler errors are resolved

[DRK3]

At the end of the WACI BDD tests there are short time.Sleep calls. These are here since, without them, messages like these get logged:

 [aries-framework/http] 2022/01/31 23:55:13 UTC - http.processPOSTRequest -> ERROR %!w(*fmt.wrapError=&{failed to unpack msg from http: unpack: authcrypt Unpack: failed to get key from kms: getKeySet: failed to read json keyset from reader: cannot read data for keysetID vnVIAAmNqGV7scUfhBNhzIh00kGHHfIJH_TjlmjQ-84: failed to get DB entry: leveldb: closed 0xc00788ca60}) - returning Code: 500
 [aries-framework/http] 2022/01/31 23:55:13 UTC - http.(*OutboundHTTPClient).Send -> ERROR didcomm failed : transport=http serviceEndpoint=http://localhost:57322 status=500 Internal Server Error errMsg=failed to unpack msg
 [aries-framework/issuecredential/service] 2022/01/31 23:55:13 UTC - issuecredential.(*Service).startInternalListener -> ERROR abandoning: action done: outboundDispatcher.Send: failed to send msg using outbound transport: received unsuccessful POST HTTP status from agent [http://localhost:57322, 500 Internal Server Error failed to unpack msg
]
 [aries-framework/issuecredential/service] 2022/01/31 23:55:13 UTC - issuecredential.(*Service).startInternalListener -> ERROR listener handle: action done: failed to fetch connection record: failed to check if connection exists: failed to get data from persistent store: failed to query store: failed to get database keys matching query: failed to get tag map: failed to get tag map: failed to get DB entry: leveldb: closed

It seems that the Aries agent has some sort of service running that does some sort of storage operation after the store provider is closed. There should be some proper way to solve this issue without the time.Sleep calls.