Does Azure AD B2C login page send the credentials in clear text over the network or does it encrypt the credentials for instance with a public key before sending them over the network?
The idea is to understand if there is a way to prevent clear text credentials over the network. In case of something leaks, it is not the real password.
The follow up question is, what about OpenID Connect and SAML do they support a feature that would help avoid clear text passwords from travelling over the network?
No, the password is set in the clear.
It's encrypted at the transport layer (https). It won't allow connections over http.
Both SAML and OIDC allow encrypted tokens to be returned to the app.