Add a banner to encrypted rooms with visible history. (#4738)

* feat: Add history visible alert.

- Adds a dismissable alert that is displayed whenever the user
  opens a room with `history_visibility` != `joined`. When cleared,
  this is recorded in the app's data store.
- When opening a room with `history_visibility` = `joined`, this
  flag is cleared.

Issue: element-hq/element-meta#2875

* tests: Add unit tests for history sharing in `RoomScreenFooterView`.

* feat: Rename flag to `hasSeenHistoryVisibleBannerRooms`, document.

* refactor: Merge enum variants, use function for banner description.

* feat: Use `AppSettings.historyVisibleDetailsURL` over hard-coded value.

* tests: Correct potential race condition with deferred assertion.

* chore: Use Localazy translation string over project-defined.

* fix: Final tweaks and review comments.

* chore: Checkout `Enterprise` submodule.

* tests: Final fixes.

ElementX/Sources/Application/Settings/AppSettings.swift

@@ -32,6 +32,7 @@ final class AppSettings {
         case seenInvites
         case hasSeenSpacesAnnouncement
         case hasSeenNewSoundBanner
+        case acknowledgedHistoryVisibleRooms
         case appLockNumberOfPINAttempts
         case appLockNumberOfBiometricAttempts
         case timelineStyle
@@ -125,6 +126,7 @@ final class AppSettings {
                   deviceVerificationURL: URL,
                   chatBackupDetailsURL: URL,
                   identityPinningViolationDetailsURL: URL,
+                  historyVisibleDetailsURL: URL,
                   elementWebHosts: [String],
                   accountProvisioningHost: String,
                   bugReportApplicationID: String,
@@ -144,6 +146,7 @@ final class AppSettings {
         self.deviceVerificationURL = deviceVerificationURL
         self.chatBackupDetailsURL = chatBackupDetailsURL
         self.identityPinningViolationDetailsURL = identityPinningViolationDetailsURL
+        self.historyVisibleDetailsURL = historyVisibleDetailsURL
         self.elementWebHosts = elementWebHosts
         self.accountProvisioningHost = accountProvisioningHost
         self.bugReportApplicationID = bugReportApplicationID
@@ -171,6 +174,10 @@ final class AppSettings {
     @UserPreference(key: UserDefaultsKeys.hasSeenNewSoundBanner, defaultValue: true, storageType: .userDefaults(store))
     var hasSeenNewSoundBanner
     
+    /// The Set of room identifiers that the user has acknowledged have visible history.
+    @UserPreference(key: UserDefaultsKeys.acknowledgedHistoryVisibleRooms, defaultValue: [], storageType: .userDefaults(store))
+    var acknowledgedHistoryVisibleRooms: Set<String>
+    
     /// The initial set of account providers shown to the user in the authentication flow.
     ///
     /// Account provider is the friendly term for the server name. It should not contain an `https` prefix and should
@@ -202,6 +209,8 @@ final class AppSettings {
     private(set) var chatBackupDetailsURL: URL = "https://element.io/help#encryption5"
     /// A URL where users can go read more about identity pinning violations
     private(set) var identityPinningViolationDetailsURL: URL = "https://element.io/help#encryption18"
+    /// A URL where users can go to read more about room history sharing.
+    private(set) var historyVisibleDetailsURL: URL = "https://element.io/en/help#e2ee-history-sharing"
     /// Any domains that Element web may be hosted on - used for handling links.
     private(set) var elementWebHosts = ["app.element.io", "staging.element.io", "develop.element.io"]
     /// The domain that account provisioning links will be hosted on - used for handling the links.