Add metrics for tracking rendezvous method used

cc: @cohosh

This is a follow-up to !214 (closed) for adding metrics for tracking the rendezvous method used by clients at the broker side.

• Adds the following entries to the broker logs accessed at /metrics to track the number of clients accepted or denied for each rendezvous method:

client-http-denied-count 8
client-http-restricted-denied-count 8
client-http-unrestricted-denied-count 0
client-snowflake-http-match-count 0
client-ampcache-denied-count 0
client-ampcache-restricted-denied-count 0
client-ampcache-unrestricted-denied-count 0
client-snowflake-ampcache-match-count 0
client-sqs-denied-count 0
client-sqs-restricted-denied-count 0
client-sqs-unrestricted-denied-count 0
client-snowflake-sqs-match-count 0

• The ClientPollTotal metric on prometheus is also updated to include the rendezvous method used.

This Merge Request relates to the following Issues and Merge Requests:

• original merge request for supporting SQS rendezvous: !214 (closed)
• original issue for implementing SQS rendezvous: #26151 (closed)
• issue for tracking SQS rendezvous deployment: #40323 (closed)