fix(zarf): return error from Execute

[AustinAbro321]

Description

This is just to make sure the wait fix test will work with uds-cli. This includes a recent change to the zarf root command Execute() now returning an error.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed

Discovered output difference when zarf returns error

[emoskito]

This change seems to display a redundant error message. For example, if I try to delete a non-existent package

Expected (v0.28.2):

$ uds version
v0.28.2
$ uds zarf p remove foo
2026-02-21 20:59:41 ERR unable to load the package: secrets "zarf-package-foo" not found

Actual:

$ ./build/uds-mac-apple zarf p remove foo
2026-02-21 21:01:48 ERR unable to load the package: secrets "zarf-package-foo" not found
     ERROR:  unable to load the package: secrets "zarf-package-foo" not found

[brandtkeller]

Previously zarf was executing an os.Exit(1) instead of returning an error. Updated to perform the same for parity. Open to other workflows.