CONSOLE-4527: Fix type errors arising after turning StrictNullChecks to 'true'

[krishagarwal278]

Total Number of Errors in a particular directory:
npx tsc --noEmit | wc -l

1400+ type errors fixed: total errors stand at 11,960

[openshift-ci-robot]

@krishagarwal278: This pull request references CONSOLE-4527 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the spike to target the "4.20.0" version, but no target version was set.

In response to this:

Total Number of Errors in a particular directory:
npx tsc --noEmit | wc -l

1800+ type errors fixed: total errors stand at 11,960

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[openshift-ci-robot]

@krishagarwal278: This pull request references CONSOLE-4527 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the spike to target the "4.20.0" version, but no target version was set.

In response to this:

Total Number of Errors in a particular directory:
npx tsc --noEmit | wc -l

1400+ type errors fixed: total errors stand at 11,960

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: krishagarwal278
Once this PR has been reviewed and has the lgtm label, please assign mylanos for approval. For more information see the Code Review Process.

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

Needs approval from an approver in each of these files:

• frontend/OWNERS

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

[openshift-ci]

@krishagarwal278: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/okd-scos-e2e-aws-ovn	fb3defa	link	false	/test okd-scos-e2e-aws-ovn
ci/prow/frontend	fb3defa	link	true	/test frontend
ci/prow/images	fb3defa	link	true	/test images
ci/prow/analyze	fb3defa	link	true	/test analyze
ci/prow/e2e-gcp-console	fb3defa	link	true	/test e2e-gcp-console

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.