feat(i18n): 온보딩 시작하기 문구를 I18n 키로 통일한다

SodaLive/Sources/I18n/I18n.swift

@@ -3906,6 +3906,12 @@ If you block this user, the following features will be restricted.
         }
     }
 
+    enum Onboarding {
+        static var startAction: String {
+            pick(ko: "시작하기", en: "Get started", ja: "始める")
+        }
+    }
+
     enum MyPage {
         enum Common {
             static var totalPrefix: String {

SodaLive/Sources/Onboarding/OnboardingView.swift

@@ -47,7 +47,7 @@ struct OnboardingView: View {
                         UIPageControl.appearance().currentPageIndicatorTintColor = UIColor(hex: "1313BC")
                     }
                     
-                    Text("시작하기")
+                    Text(I18n.Onboarding.startAction)
                         .appFont(size: 18.3, weight: .bold)
                         .foregroundColor(.white)
                         .frame(width: screenSize().width, height: 60)