Update 'Upload data files' with steps for the new file import process

[vishaangelova]

Summary

This PR:

• Updates the Upload a file section in the Sample data doc to remove unnecessary screenshot and add a reference to the Upload data files doc.
• Adds an applies-switch to update the steps described in the Upload data files doc, and include the new workflow since in 9.2 ([ML] Redesigns file upload UX kibana#232923). Also removes an unnecessary screenshot in this doc.

Resolves #3243

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

Preview

manage-data/ingest/sample-data.md
manage-data/ingest/upload-data-files.md

[github-actions]

Vale Linting Results

Summary: 3 suggestions found

💡 Suggestions (3)

File	Line	Rule	Message
manage-data/ingest/upload-data-files.md	27	Elastic.Wordiness	Consider using 'drag' instead of 'drag and drop'.
manage-data/ingest/upload-data-files.md	47	Elastic.Wordiness	Consider using 'drag' instead of 'drag and drop'.
manage-data/ingest/upload-data-files.md	61	Elastic.Wordiness	Consider using 'drag' instead of 'drag and drop'.

[github-actions]

🔍 Preview links for changed docs

• manage-data/ingest/sample-data.md
• manage-data/ingest/upload-data-files.md

[jgowdyelastic]

LGTM

[georgewallace]

Updates look good to me. Thanks for removing the screenshots!

[bmorelli25]

As Stack 9.2 and Serverless are identical, can we combine these into a single tab instead of two? I've seen this pattern elsewhere, for example:

• https://www.elastic.co/docs/solutions/security/ai/attack-discovery#attack-discovery-rbac
• https://www.elastic.co/docs/solutions/security/get-started/automatic-migration

But our cumulative docs guidelines aren't clear about what the recommended pattern is. Do you know? The applies-switch docs also don't cover this.

[bmorelli25]

Ah wait, it is covered here:

You can specify multiple applies_to definitions in a single applies-item using YAML object notation with curly braces {}. This is useful when content applies to multiple deployment types or versions simultaneously.