Rename SSL parameters

[steveny91]

What does this PR do?

Change the variable from camelCase to snake_case to keep consistency with other params

Motivation

QA for #12541

Other

In the future we should deprecate a lot of the ssl_* params that we still have in the check. The newly added ones tls_* are their replacement and seems like the ssl_* ones are deprecated:

https://pymongo.readthedocs.io/en/stable/api/pymongo/mongo_client.html#pymongo.mongo_client.MongoClient

version 3.9 (3.11.4+ is shipped starting Agent 7.30):
ssl_cert_reqs was deprecated in favor of tls_allow_invalid_certificates.
ssl_match_hostname was deprecated in favor of tls_allow_invalid_hostnames.
ssl_ca_certs was deprecated in favor of tls_ca_file.
ssl_certfile was deprecated in favor of tls_certificate_key_file.
ssl_crlfile was deprecated in favor of tlsCRLFile.
ssl_pem_passphrase was deprecated in favor of tlsCertificateKeyFilePassword.

version 3.12(3.12.3+ is shipped with agent 7.36):
ssl_certfile and ssl_keyfile were deprecated in favor of tls_certificate_key_file.

[codecov]

Codecov Report

Merging #12743 (840ae88) into master (a3d3bde) will not change coverage.
The diff coverage is n/a.

Flag	Coverage Δ
mongo	95.68% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.