Custom reloader init containers cannot start in vmauth and vmagent pods

[ebensom]

The PR #667 introduced using custom reloader init containers for vmauth and vmagent to initialize the configuration.
However there is a bug in the PR blocking the init containers to execute properly:

flag provided but not defined: -mode
v0.38.0

The config-reloader application introduced the --only-init-config for the initialization scenario (i.e. to exit from waiting for subsequent events during watcher initialization), however the vm-operator factory code uses --mode=one-shot argument.

[f41gh7]

Fix included to the https://github.com/VictoriaMetrics/operator/releases/tag/v0.39.0 release