[CHORE] Remove code and support for servers below 0.62.0

[cardoso]

@RocketChat/ios

Closes #2026

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (develop@932f7ea). Click here to learn what that means.
The diff coverage is 27.27%.

@@            Coverage Diff            @@
##             develop   #2448   +/-   ##
=========================================
  Coverage           ?   26.2%           
=========================================
  Files              ?     448           
  Lines              ?   16678           
  Branches           ?       0           
=========================================
  Hits               ?    4371           
  Misses             ?   12307           
  Partials           ?       0

Impacted Files	Coverage Δ
...scriptionManager/SubscriptionManagerMessages.swift	0% <ø> (ø)
...ocket.Chat/Managers/Model/CustomEmojiManager.swift	0% <0%> (ø)
Rocket.Chat/API/Clients/PushClient.swift	0% <0%> (ø)
Rocket.Chat/API/Clients/MessagesClient.swift	57.97% <25%> (ø)
Rocket.Chat/API/Clients/SubscriptionsClient.swift	59.6% <40%> (ø)

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[rafaelks]

<3