fix(plugin-cloud-storage): file sizes use correct mime type (#11633)

### What?

Fixes #7575

### Why?

The bug was caused by using the upload file mimeType instead of the
resized file mime types.

Often, the resized file will have a different mime type (ex: converting
all files to jpg) so this is incorrect.

### How?

Use the resizedFile mime type with the upload file mimeType as a backup

I'm unsure when/why the resized files wouldn't have a mime type, but the
base file mime type is a sensible backup option.

Author: 6TELOIV

packages/payload-cloud/src/utilities/getIncomingFiles.ts

@@ -26,13 +26,13 @@ export function getIncomingFiles({
 
     if (data?.sizes) {
       Object.entries(data.sizes).forEach(([key, resizedFileData]) => {
-        if (req.payloadUploadSizes?.[key] && data.mimeType) {
+        if (req.payloadUploadSizes?.[key] && resizedFileData.mimeType) {
           files = files.concat([
             {
               buffer: req.payloadUploadSizes[key],
               filename: `${resizedFileData.filename}`,
               filesize: req.payloadUploadSizes[key].length,
-              mimeType: data.mimeType,
+              mimeType: resizedFileData.mimeType,
             },
           ])
         }

packages/plugin-cloud-storage/src/utilities/getIncomingFiles.ts

@@ -27,13 +27,13 @@ export function getIncomingFiles({
 
     if (data?.sizes) {
       Object.entries(data.sizes).forEach(([key, resizedFileData]) => {
-        if (req.payloadUploadSizes?.[key] && data.mimeType) {
+        if (req.payloadUploadSizes?.[key] && resizedFileData.mimeType) {
           files = files.concat([
             {
               buffer: req.payloadUploadSizes[key],
               filename: `${resizedFileData.filename}`,
               filesize: req.payloadUploadSizes[key].length,
-              mimeType: data.mimeType,
+              mimeType: resizedFileData.mimeType,
             },
           ])
         }