When helmfile template --args is used, the extra flags were being
passed to helm repo update and helm repo add commands, which don't
support all flags that helm template/install support. This caused
failures when flags like --dry-run were passed via --args.
The fix saves the extra flags before executing helm repo commands,
clears them, and restores them afterwards to ensure repo commands
run without unsupported flags.
Fixes CI issue in PR #2378 where test issue-1749 fails
with "Error: unknown flag: --dry-run" during helm repo update.
Signed-off-by: yxxhero <aiopsclub@163.com>