Add missing online functionality for the image pull secret template functions

[sgalsaleh]

What this PR does / why we need it:

• Adds missing online functionality for the image pull secret template functions where it only worked for airgap.
• Fixes the image pull secret name in airgap mode to use the same pattern kots (<app-slug>-registry).
• Removes the auth field from the airgap settings as it's extra (it doesn't exist in kots).

Which issue(s) this PR fixes:

SC-128060

Does this PR require a test?

Yes

Does this PR require a release note?

NONE

Does this PR require documentation?

NONE

[diamonwiggins]

has looked good to me so far, but integration tests are failing

[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-7e03295" -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-7e03295?airgap=true" -H "Authorization: $EC_SMOKE_TEST_LICENSE_ID" -o embedded-cluster-smoke-test-staging-app-ci.tgz

Happy debugging!

[diamonwiggins]

lgtm

[sgalsaleh]

Failing tests are not relevant to the PR and are flaky.