fix: Cast port to int in ClusterNode connection string parsing

[omirandadev]

What this PR does / why we need it:

Fix _parse_connection_string in both redis.py and eg_valkey.py to cast the port to int and guard against malformed entries. The ClusterNode constructor requires port as an integer, but the parser was passing it as a string via dict(zip(...)), causing TypeError: ClusterNode.__init__() missing 1 required positional argument: 'port'

Which issue(s) this PR fixes:

Checks

• I've made sure the tests are passing.
• My commits are signed off (git commit -s)
• My PR title follows conventional commits format

Testing Strategy

• Unit tests
• Integration tests
• Manual tests
• Testing is not required for this change

Misc

[vanitabhagwat]

LGTM