[Infra] Silence extensions warnings in Sessions SDK tests (#13629)

Author: ncooke3

FirebaseSessions/Tests/Unit/Error+EquatableTests.swift

@@ -23,7 +23,7 @@ import XCTest
 /// This class exists for unit testing purposes only. The SDK should use switch internally
 /// when handling errors, because equating errors is prone to issues (eg. we're just comparing
 /// the types, but not the values).
-extension FirebaseSessionsError: Equatable {
+extension FirebaseSessionsError: Swift.Equatable {
   public static func == (lhs: FirebaseSessions.FirebaseSessionsError,
                          rhs: FirebaseSessions.FirebaseSessionsError) -> Bool {
     return String(reflecting: lhs) == String(reflecting: rhs)