[IMPROVEMENT] Add editing changed handler to UITextField in connect screen

[blewjy]

@RocketChat/ios

Closes #2477

This PR address the issue of the UITextField in the connect screen not behaving as expected, where the cursor jumps to the end of the text when editing in the middle of the text.

This problem was mainly caused by the delegate method shouldChangeCharactersIn where the whole text was replaced with every edit. I noticed that this was primarily to trigger the textFieldDidChange() method to toggle the connect button.

My solution was to instead add a listener to the textField for whenever a change was detected, and the handler function being the same textFieldDidChange() method. As a result the shouldChangeCharactersIn method is unused and I have removed it.

Hope my solution is ideal for the problem. Please let me know if there are any changes needed to be made. Thank you! 😊

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #2494 into develop will increase coverage by 0.12%.
The diff coverage is 0%.

@@             Coverage Diff             @@
##           develop    #2494      +/-   ##
===========================================
+ Coverage    26.22%   26.35%   +0.12%     
===========================================
  Files          456      456              
  Lines        16935    16929       -6     
===========================================
+ Hits          4442     4462      +20     
+ Misses       12493    12467      -26

Impacted Files	Coverage Δ
...Controllers/Auth/ConnectServerViewController.swift	60.2% <0%> (+1.78%)	⬆️
...ocket.Chat/Extensions/Models/ObjectExtension.swift	80% <0%> (-20%)	⬇️
...ontrollers/Base/Main/MainSplitViewController.swift	45% <0%> (-7.5%)	⬇️
...Chat/Controllers/Chat/MessagesViewController.swift	31.48% <0%> (-2.98%)	⬇️
Rocket.Chat/Managers/PushManager.swift	27.58% <0%> (+3.44%)	⬆️
Rocket.Chat/Managers/AppManager.swift	40.58% <0%> (+4.11%)	⬆️
Rocket.Chat/Extensions/Models/AuthExtensions.swift	100% <0%> (+33.33%)	⬆️
...anagers/Model/AuthManager/AuthManagerRecover.swift	96.96% <0%> (+60.6%)	⬆️

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[rafaelks]

Looking great! Thank you @blewjy!