[Payload] Fix mime type handling for Azure storage

### Describe the Bug When uploads are configured to use temporary files, the mime types are not stored with the blob object in azure storage. The fix is an easy one-liner. In addition to the abort signal here: https://github.com/payloadcms/payload/blob/94d224926ec98bd9f86a40d35c9c20fa54777a05/packages/storage-azure/src/handleUpload.ts#L37 There just needs to be the content type header: ```js blobHTTPHeaders: { blobContentType: file.mimeType } ``` I'll create a PR to fix this next. ### Link to the code that reproduces this issue https://github.com/thearc-hq/oss-payload/blob/test-azure-svg-upload/test/_community/int.spec.ts#L28 ### Reproduction Steps 1. Configure uploads to use temporary files 2. Use azure storage adapter 3. Upload an Image file via Web UI 4. Check the content-type header when downloading the file (it is `application/octet-stream`) ### Which area(s) are affected? plugin: storage-* ### Environment Info ```text I think we don't need this. ```