error out if users try to change Zarf deployed services credentials on re-init

[AustinAbro321]

Is your feature request related to a problem? Please describe.

When a user attempts to update the credentials of Zarf-deployed service using zarf init and flags such as --artifact-*, --registry-*, or `--git- with values different from the existing ones, they receive a warning that these services cannot be updated during a re-init. Instead of ignoring these flags, we should require users to execute the command with flags that are not ignored.

Describe the solution you'd like

• Given I have a cluster already initialized with a registry pull password of "original-value"
• When I run zarf init --registry-pull-password="new-value"
• Then Zarf errors out immediately and tells me to use zarf tools update-creds

Describe alternatives you've considered

One alternative to consider would be actually allowing the credentials to be changed on re-init. IMO better to keep things simple for now and keep these commands separate, even if we implemented this issue, we could always change to allowing in the future if users ask for it.