Allow --ingress-class-name to be specified in chart

[jacobsalway]

Purpose of this PR

• Allow the --ingress-class-name argument to be specified to the controller. This is currently not exposed.

Related: #2276

Change Category

• Bugfix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that could affect existing functionality)
• Documentation update

Checklist

• I have conducted a self-review of my own code.
• I have updated documentation accordingly.
• I have added tests that prove my changes are effective or that my feature works.
• Existing unit tests pass locally with my changes.

[jacobsalway]

/assign @ChenYi015 @ImpSy

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ChenYi015

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[ChenYi015]

/lgtm