Remove credentials before printing Redis subscriptions

[itowlson]

Fixes #2341.

@seungjin can you test this please? I don't have a Redis instance that accepts credentials, and due to a separate issue that seems to prevent me from checking the output. Thanks!

[karthik2804]

Tested using a redis-labs instance and it looks good!

[itowlson]

Aha, thank you for the proper test @karthik2804!

[seungjin]

# spin --version
spin 2.4.0-pre0 (e82985ba 2024-03-12)

AND 

Active Channels on redis://redis-XXXXX.XXX.ap-northeast-1-2.ec2.cloud.redislabs.com:12537:
	redis://redis-XXXXX.XXX.ap-northeast-1-2.ec2.cloud.redislabs.com:12537:postbox: [postbox]

Works!