Handle sudo connection in the account view

[sbesson]

Fixes #445

Summary of changes

• expand webadmin.views.my_account to also detect whether the current context was created via sudo
• If the current session was created with sudo, disable the ability to update experimenter properties and password in the UI

To test this PR, follow the authentication workflow described in https://github.com/ome/omero-web/issues/445#issuecomment-1525079385 i.e.

1. create a session using --sudo via the CLI
2. use the session key as the username/password to authenticate using OMERO.web
3. got to the My Account view i.e. click on the user profile then User settings

Without this PR, the Save and Change my password button should be active. Clicking on Save should launch the 500 error page with a server SecurityViolation of type Current user is not admin for the given user(s). Clicking on Change my password will ask for the current user password which is not known in this workflow since the session was created using the principal password.

With this PR, both buttons should be hidden.

[sbesson]

Thanks @knabar, the approach of the last commit makes sense to me. Passing back to @will-moore and @pwalczysko for another round of review.

[will-moore]

Looks good - form is "inert":

[pwalczysko]

confirming, lgtm