[bug]: Normalize webhook endpoint URL before validation in create/edit commands

[PrasunaEnumarthy]

Description

The non-interactive webhook commands (harbor webhook create and harbor webhook edit) validate the --endpoint-url directly without normalizing it first. This is inconsistent with other Harbor CLI commands that normalize URLs using FormatUrl(...) before validation.

Steps to Reproduce

1. Run command:
   harbor webhook create --endpoint-url example.com/webhook
2. Or:
   harbor webhook edit --endpoint-url example.com/webhook
3. Observe that the command may reject the URL due to a missing scheme (http:// or https://)

Expected Behavior

The CLI should normalize the input URL before validation.

Example:
example.com/webhook → https://example.com/webhook

After normalization, the URL should pass validation.

Actual Behavior

The CLI validates the raw input directly.
As a result, URLs without a scheme (such as example.com/webhook) may fail validation, even though similar inputs are accepted in other commands.

Environment

• OS: Not specified
• Tool version: latest
• Other relevant details: N/A

Additional Context

Other Harbor CLI commands (e.g., registry update) normalize URLs using FormatUrl(...) before validation. The webhook commands should follow the same pattern for consistency.