Add bundling option for image handler function

Sharp recommends to exclude the library from bundling
Reference: https://sharp.pixelplumbing.com/install#esbuild

Author: gsingh04

source/constructs/lib/back-end/back-end-construct.ts

@@ -106,6 +106,20 @@ export class BackEnd extends Construct {
         DEFAULT_FALLBACK_IMAGE_BUCKET: props.fallbackImageS3Bucket,
         DEFAULT_FALLBACK_IMAGE_KEY: props.fallbackImageS3KeyBucket,
       },
+      bundling: {
+        externalModules: ["sharp"],
+        commandHooks: {
+          beforeBundling(inputDir: string, outputDir: string): string[] {
+            return [];
+          },
+          beforeInstall(inputDir: string, outputDir: string): string[] {
+            return [];
+          },
+          afterBundling(inputDir: string, outputDir: string): string[] {
+            return [`cd ${outputDir}`, "npm install --arch=x64 --platform=linux sharp"];
+          },
+        },
+      },
     });
 
     const imageHandlerLogGroup = new LogGroup(this, "ImageHandlerLogGroup", {