Fix cleaning up helm values before install / upgrade

[sgalsaleh]

What this PR does / why we need it:

Fixes an issue when cleaning up helm values before install / upgrade where []map[string]interface{} types weren't handled, which broke admin console upgrades in some scenarios.

Which issue(s) this PR fixes:

Does this PR require a test?

Does this PR require a release note?

NONE

Does this PR require documentation?

NONE

[github-actions]

This PR has been released (on staging) and is available for download with a embedded-cluster-smoke-test-staging-app license ID.

Online Installer:

curl "https://staging.replicated.app/embedded/embedded-cluster-smoke-test-staging-app/ci/appver-dev-f4dc9d7" -H "Authorization: $EC_SMOKE_TEST_LICENSE_ID" -o embedded-cluster-smoke-test-staging-app-ci.tgz

Airgap Installer (may take a few minutes before the airgap bundle is built):

curl "https://staging.replicated.app/embedded/embedded-cluster-smoke-test-staging-app/ci-airgap/appver-dev-f4dc9d7?airgap=true" -H "Authorization: $EC_SMOKE_TEST_LICENSE_ID" -o embedded-cluster-smoke-test-staging-app-ci.tgz

Happy debugging!