Use namespaces in the default providers (#1262)

Author: a-maurice

app_check/src/include/firebase/app_check/app_attest_provider.h

@@ -37,7 +37,7 @@ class AppAttestProviderFactory : public AppCheckProviderFactory {
   /// Gets the AppCheckProvider associated with the given
   /// {@link App} instance, or creates one if none
   /// already exists.
-  AppCheckProvider* CreateProvider(App* app) override;
+  firebase::app_check::AppCheckProvider* CreateProvider(App* app) override;
 
  private:
   AppAttestProviderFactory();

app_check/src/include/firebase/app_check/debug_provider.h

@@ -43,7 +43,7 @@ class DebugAppCheckProviderFactory : public AppCheckProviderFactory {
   /// Gets the AppCheckProvider associated with the given
   /// {@link App} instance, or creates one if none
   /// already exists.
-  AppCheckProvider* CreateProvider(App* app) override;
+  firebase::app_check::AppCheckProvider* CreateProvider(App* app) override;
 
  private:
   DebugAppCheckProviderFactory();

app_check/src/include/firebase/app_check/device_check_provider.h

@@ -37,7 +37,7 @@ class DeviceCheckProviderFactory : public AppCheckProviderFactory {
   /// Gets the AppCheckProvider associated with the given
   /// {@link App} instance, or creates one if none
   /// already exists.
-  AppCheckProvider* CreateProvider(App* app) override;
+  firebase::app_check::AppCheckProvider* CreateProvider(App* app) override;
 
  private:
   DeviceCheckProviderFactory();

app_check/src/include/firebase/app_check/play_integrity_provider.h

@@ -37,7 +37,7 @@ class PlayIntegrityProviderFactory : public AppCheckProviderFactory {
   /// Gets the AppCheckProvider associated with the given
   /// {@link App} instance, or creates one if none
   /// already exists.
-  AppCheckProvider* CreateProvider(App* app) override;
+  firebase::app_check::AppCheckProvider* CreateProvider(App* app) override;
 
  private:
   PlayIntegrityProviderFactory();