Backport: feat(openai): add opt-in pass-through for unsupported file media types

[github-actions]

This is an automated backport of #15297 to the release-v6.0 branch. FYI @aayush-kapoor
This backport has conflicts that need to be resolved manually.

git cherry-pick output

Auto-merging content/providers/01-ai-sdk-providers/03-openai.mdx
Auto-merging packages/openai/src/responses/convert-to-openai-responses-input.test.ts
Auto-merging packages/openai/src/responses/convert-to-openai-responses-input.ts
CONFLICT (content): Merge conflict in packages/openai/src/responses/convert-to-openai-responses-input.ts
Auto-merging packages/openai/src/responses/openai-responses-language-model.ts
Auto-merging packages/openai/src/responses/openai-responses-options.ts
error: could not apply 685cec7fc... feat(openai): add opt-in pass-through for unsupported file media types (#15297)
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".
hint: Disable this message with "git config set advice.mergeConflict false"

[github-actions]

🚀 Published in:

Package	Version
ai	6.0.183
@ai-sdk/amazon-bedrock	4.0.106
@ai-sdk/angular	2.0.184
@ai-sdk/anthropic	3.0.78
@ai-sdk/azure	3.0.65
@ai-sdk/gateway	3.0.115
@ai-sdk/google	3.0.74
@ai-sdk/google-vertex	4.0.129
@ai-sdk/langchain	2.0.189
@ai-sdk/llamaindex	2.0.183
@ai-sdk/openai	3.0.64
@ai-sdk/react	3.0.185
@ai-sdk/rsc	2.0.183
@ai-sdk/svelte	4.0.183
@ai-sdk/vue	3.0.183