Fixes #225 - Use a properly defined user agent

* Set a proper user agent
* Add fallback when UA comes out nil
* Remove unused Bundle extension
* Return nil when asciification fails
* Add whitespace handling and further emoji test case
* Explicitly check if string is already in ASCII
* Rename factory to builder
* Use allSatisfy instead of reduce
* Use key path syntax

ElementX/Sources/Services/UserSessionStore/UserSessionStore.swift

@@ -109,7 +109,8 @@ class UserSessionStore: UserSessionStoreProtocol {
         let builder = ClientBuilder()
             .basePath(path: baseDirectory.path)
             .username(username: credentials.userID)
-        
+            .userAgent(userAgent: UserAgentBuilder.makeASCIIUserAgent() ?? "unknown")
+
         do {
             let client: Client = try await Task.dispatch(on: .global()) {
                 let client = try builder.build()