Fix: google storage init with sa and download

[kazukitakamatsu]

Description

Fixed two problems when using Google Storage (STORAGE_TYPE=google-storage).

• When Service Account is specified, an error occurs when invoking init.
  • from_service_account_info() needs to specify a JSON object, not a JSON string
  • Change to pass after changing to a JSON object
• Error occurs when worker calls download when uploading files, etc.
  • Before the change, download_blob() does not exist.
  • Changed to use download_to_filename()

Fixes # (issue)

• none

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• manual test

1. Create a Google Storage bucket
2. Create Service Account
3. Set a key to the created Service Account
4. Download and Base64 encode the key
5. Specify STORAGE_TYPE, GOOGLE_STORAGE_BUCKET_NAME, GOOGLE_STORAGE_SERVICE_ACCOUNT_JSON_BASE64 in environment variables

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods
• optional I have made corresponding changes to the documentation
• optional I have added tests that prove my fix is effective or that my feature works
• optional New and existing unit tests pass locally with my changes