validate service with mixed protocols

[nckturner]

What type of PR is this?

Uncomment only one, leave it on its own line:

/kind cleanup

What this PR does / why we need it:

Which issue(s) this PR fixes:
Cherry pick kubernetes/kubernetes#105361 from upstream. This is required until we explicitly support mixed protocols in the external CCM.

The AWS in-tree controller doesn't support mixed protocols for service. This PR adds validation logic to the AWS cloudprovider to not provision any load balancer for service with mixed protocols so that the MixedProtocolLBService feature gate can be enabled safely on AWS.

kubernetes/enhancements#1435

Special notes for your reviewer:

Manually tested with feature-gate MixedProtocolLBService=true

• services with mixed protocol do not get reconciled, controller reports event "... mixed protocol is not supported for LoadBalancer"
• CLB with TCP works as expected, CLB with UDP does not get reconciled as usual
• NLB with TCP, or NLB with UDP protocol is functional
• empty protocol defaults to TCP

Does this PR introduce a user-facing change?:

NONE

[kishorj]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kishorj, nckturner

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [nckturner]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment