fix: Ensure file uploads use RFC 7578 standard for multipart arrays

See new docs from Speakeasy folks:

https://www.speakeasy.com/docs/speakeasy-reference/generation/gen-yaml#multipartarrayformat

Remove the work around in `MultipartFileFieldFixHook` now that
`multipartArrayFormat: standard` handles RFC 7578 compliance at code
generation time.

Author: rwjblue-glean

.speakeasy/gen.yaml

@@ -29,6 +29,7 @@ generation:
     generateTests: true
     generateNewTests: true
     skipResponseBodyAssertions: true
+  multipartArrayFormat: standard
 python:
   version: 0.11.22
   additionalDependencies:

src/glean/api_client/_hooks/multipart_fix_hook.py

@@ -1,5 +1,4 @@
 from .types import Hooks
-from .multipart_fix_hook import MultipartFileFieldFixHook
 from .agent_file_upload_error_hook import AgentFileUploadErrorHook
 
 
@@ -14,8 +13,5 @@ def init_hooks(hooks: Hooks):
     with an instance of a hook that implements that specific Hook interface
     Hooks are registered per SDK instance, and are valid for the lifetime of the SDK instance"""
 
-    # Register hook to fix multipart file field names that incorrectly have '[]' suffix
-    hooks.register_sdk_init_hook(MultipartFileFieldFixHook())
-
     # Register hook to provide helpful error messages for agent file upload issues
     hooks.register_after_error_hook(AgentFileUploadErrorHook())