Fix posting images on web (#7105)

* Fix uploadBlob to handle blob: URI

* Patch expo-image-manipulator to support "compress" argument

* Narrow down the fix

src/lib/api/upload-blob.web.ts

@@ -11,7 +11,10 @@ export async function uploadBlob(
   input: string | Blob,
   encoding?: string,
 ): Promise<ComAtprotoRepoUploadBlob.Response> {
-  if (typeof input === 'string' && input.startsWith('data:')) {
+  if (
+    typeof input === 'string' &&
+    (input.startsWith('data:') || input.startsWith('blob:'))
+  ) {
     const blob = await fetch(input).then(r => r.blob())
     return agent.uploadBlob(blob, {encoding})
   }