Mark selected language as active in dropdown

[esoergel]

Product Description

Show currently selected language as "active" in the web apps language selection dropdown

This also makes the selected language no longer clickable.

Technical Summary

https://dimagi.atlassian.net/browse/USH-5114

Shout out to @avazirna for #35444

Feature Flag

Safety Assurance

Safety story

This is pretty straightforward a change - I'm happy with local testing

Automated test coverage

QA Plan

Rollback instructions

• This PR can be reverted after deploy with no further considerations

Labels & Review

• Risk label is set correctly
• The set of people pinged as reviewers is appropriate for the level of risk of the change

[MartinRiese]

I wonder if it would be better to put this in MenuDropdownView.childViewOptions so UsersModels.getCurrentUser() only need the be called once. And maybe only if languageOptionsEnabled is true.

[esoergel]

getCurrentUser is cached actually, so it shouldn't be a problem to call it more than once:

commcare-hq/corehq/apps/cloudcare/static/cloudcare/js/formplayer/users/models.js

Lines 72 to 78 in 0b23168

	var userInstance;
	self.getCurrentUser = function () {
	if (!userInstance) {
	userInstance = new self.CurrentUser();
	}
	return userInstance;
	};