Implement a way to clear the Client Certificate selection on Sender-type Connectors

[andreeaharmonic]

Steps:

1. Go to Channels
2. Open any Sender-type Connector (HTTP, TCP, Web Service)
3. On TLS Settings open Client Certificates Picker and select any option
4. Observe that from this point on, the user cannot deselect and leave the picker empty as it is a single select modal with at least one selection mandatory.

Note: From this point forward the user will not be able to deactivate mTLS

Evidence:

2026-01-09.15-25-34.mp4

Workaround:
Change the connector to a different type and then change it back to the connector type you need to use. This will lose the channel configuration but will facilitate fresh TLS config without mTLS.