feat(storage-*): include modified headers into the response headers of files when using adapters

[paulpopus]

This PR makes it so that modifyResponseHeaders is supported in our adapters when set on the collection config. Previously it would be ignored.

This means that users can now modify or append new headers to what's returned by each service.

import type { CollectionConfig } from 'payload'

export const Media: CollectionConfig = {
  slug: 'media',
  upload: {
    modifyResponseHeaders: ({ headers }) => {
      const newHeaders = new Headers(headers) // Copy existing headers
      newHeaders.set('X-Frame-Options', 'DENY') // Set new header

      return newHeaders
    },
  },
}

Also adds support for void return on the modifyResponseHeaders function in the case where the user just wants to use existing headers and doesn't need more control.

eg:

import type { CollectionConfig } from 'payload'

export const Media: CollectionConfig = {
  slug: 'media',
  upload: {
    modifyResponseHeaders: ({ headers }) => {
      headers.set('X-Frame-Options', 'DENY') // You can directly set headers without returning
    },
  },
}

TODO TESTING:

• GCS
• S3
• Azure
• UploadThing
• Vercel Blob