ios build: Disable deterministic UUIDs in Podfile

This follows a change in the template app on the way to RN v0.68:
  facebook/react-native@f595a4e68 Duplicate Xcodeproj UUIDs in iOS app template Podfile fixed

The change is one that seems to be needed only with Fabric / New Arch:
  https://reactnative.dev/docs/0.68/new-architecture-app-renderer-ios#1-enable-fabric-in-podfile

But it sounds like it's working around a CocoaPods mess (one in
perhaps the same spirit as the bad caching we perennially see from
CocoaPods.)  May as well take it now.

ios/Podfile

@@ -6,6 +6,8 @@ require_relative '../node_modules/expo/scripts/autolinking.rb'
 require_relative '../node_modules/react-native/scripts/react_native_pods'
 require_relative '../node_modules/@react-native-community/cli-platform-ios/native_modules'
 
+install! 'cocoapods', :deterministic_uuids => false
+
 target 'ZulipMobile' do
   config = use_native_modules!
 

ios/Podfile.lock

@@ -757,6 +757,6 @@ SPEC CHECKSUMS:
   Yoga: c4d61225a466f250c35c1ee78d2d0b3d41fe661c
   YogaKit: f782866e155069a2cca2517aafea43200b01fd5a
 
-PODFILE CHECKSUM: 1576cc1dcc2b42d6d0484ee84b568d44a1a91346
+PODFILE CHECKSUM: 471cbe682ee7f0ba312982bb828ec78c4bd20655
 
 COCOAPODS: 1.11.3