docs(your-first-app): use correct type on "Adding Mobile" page (#3533)

Co-authored-by: Maria Hutt <[email protected]>

Author: Nozarno

docs/react/your-first-app/5-adding-mobile.md

@@ -14,7 +14,7 @@ First, we’ll update the photo saving functionality to support mobile. In the `
 
 ```tsx
 const savePicture = async (photo: Photo, fileName: string): Promise<UserPhoto> => {
-  let base64Data: string;
+  let base64Data: string | Blob;
   // "hybrid" will detect Cordova or Capacitor;
   if (isPlatform('hybrid')) {
     const file = await Filesystem.readFile({

docs/vue/your-first-app/5-adding-mobile.md

@@ -17,7 +17,7 @@ In the `savePicture` function, check which platform the app is running on. If it
 
 ```tsx
 const savePicture = async (photo: Photo, fileName: string): Promise<UserPhoto> => {
-  let base64Data: string;
+  let base64Data: string | Blob;
   // "hybrid" will detect mobile - iOS or Android
   if (isPlatform('hybrid')) {
     const file = await Filesystem.readFile({

versioned_docs/version-v7/react/your-first-app/5-adding-mobile.md

@@ -14,7 +14,7 @@ First, we’ll update the photo saving functionality to support mobile. In the `
 
 ```tsx
 const savePicture = async (photo: Photo, fileName: string): Promise<UserPhoto> => {
-  let base64Data: string;
+  let base64Data: string | Blob;
   // "hybrid" will detect Cordova or Capacitor;
   if (isPlatform('hybrid')) {
     const file = await Filesystem.readFile({

versioned_docs/version-v7/vue/your-first-app/5-adding-mobile.md

@@ -17,7 +17,7 @@ In the `savePicture` function, check which platform the app is running on. If it
 
 ```tsx
 const savePicture = async (photo: Photo, fileName: string): Promise<UserPhoto> => {
-  let base64Data: string;
+  let base64Data: string | Blob;
   // "hybrid" will detect mobile - iOS or Android
   if (isPlatform('hybrid')) {
     const file = await Filesystem.readFile({