feat(ios): allow static_framework usage via Podfile global (#3388)

First pass at addressing #3253 to allow release in 6.4.0. For v7.0.0 we should make the default value true along with the RN min version set to 0.61.x +

packages/admob/RNFBAdMob.podspec

@@ -2,14 +2,10 @@ require 'json'
 package = JSON.parse(File.read(File.join(__dir__, 'package.json')))
 
 firebase_sdk_version = '~> 6.13.0'
-using_custom_firebase_sdk_version = defined? $FirebaseSDKVersion
-if using_custom_firebase_sdk_version
-  Pod::UI.puts "RNFBAdMob: Using user specified Firebase SDK version '#{$FirebaseSDKVersion}'"
-  firebase_sdk_version = $FirebaseSDKVersion
-end
 
 Pod::Spec.new do |s|
   s.name                = "RNFBAdMob"
+
   s.version             = package["version"]
   s.description         = package["description"]
   s.summary             = <<-DESC
@@ -22,11 +18,28 @@ Pod::Spec.new do |s|
   s.social_media_url    = 'http://twitter.com/invertaseio'
   s.ios.deployment_target = "9.0"
   s.source_files        = 'ios/**/*.{h,m}'
+
+  # React Native dependencies
   s.dependency          'React'
+  s.dependency          'RNFBApp'
+
+  # Other dependencies
+  s.dependency          'PersonalizedAdConsent', '~> 1.0.4'
+
+  if defined?($FirebaseSDKVersion)
+    Pod::UI.puts "#{s.name}: Using user specified Firebase SDK version '#{$FirebaseSDKVersion}'"
+    firebase_sdk_version = $FirebaseSDKVersion
+  end
+
+  # Firebase dependencies
   s.dependency          'Firebase/Core', firebase_sdk_version
   s.dependency          'Firebase/Analytics', firebase_sdk_version
   s.dependency          'Firebase/AdMob', firebase_sdk_version
-  s.dependency          'PersonalizedAdConsent'
-  s.dependency          'RNFBApp'
-  s.static_framework    = true
+
+  if defined?($RNFirebaseAsStaticFramework)
+    Pod::UI.puts "#{s.name}: Using overridden static_framework value of '#{$RNFirebaseAsStaticFramework}'"
+    s.static_framework = $RNFirebaseAsStaticFramework
+  else
+    s.static_framework = false
+  end
 end