web-api(fix): include file or contents types in file_uploads arguments

[zimeg]

Summary

This PR ensures both the file and content arguments are included in the type for file_uploads. Fixes #1743.

Reviewers

The following snippets can be used to ensure these types are available! Using TypeScript or JSDoc is recommended to experience the full typing experience.

Single file uploads

Everything should remain working just as expected:

(async () => {
    const web = new WebClient(token);
    const result = await web.files.uploadV2({
        channel_id: "C0123456789",
        filename: "GREETINGS.txt",
        content: "hello world",
    });
    console.log(result);
})();

Multiple file uploads

Multiple file uploads can be done without needing to specify a top-level file or content. These attributes are still allowed and will be uploaded if provided, but aren't required anymore!

But the main fix of this PR is exposing the types for the file and content within file_uploads:

(async () => {
    const web = new WebClient(token);
    const result = await web.files.uploadV2({
        channel_id: "C0123456789",
        file_uploads: [
            {
                filename: "README.md",
                file: "./README.md",
            },
            {
                filename: "GREETINGS.txt",
                content: "hello world",
            },
        ]
    });
    console.log(result);
})();

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[zimeg]

📝 Some notes for the reviewers!

[zimeg]

Changes to check for the existence of file or whatever key is being done for stronger type safety. The error case would be thrown by the API and is moved ahead a bit here. I think this is also checked earlier in the call too, but isn't picked up by the types.

[zimeg]

Omit seems to act strange with union types so instead this helper type is added! The T extends T is used to force the type checker to apply the Omit to each member of the union.

[zimeg]

This Omit seems alright sense the file and content remain optional in the second case! There's magic deep within the type checker.

[seratch]

Cool! Thanks for resolving this!