docs: clarify mid vs mid2 offline license key compatibility (#5404) (CP: v24)

[mcollovati]

The download-offline-license Maven goal always generates a mid2 machine ID, but Vaadin 24.9 and earlier only accept mid keys. This causes confusing "Invalid offline key" errors.

Add a version compatibility table to the offline license section, a warning that the Maven goal only works for Vaadin 25+, and improve the related troubleshooting entry in the knowledge base.

[github-actions]

AI Language Review

In the file "Knowledge Base", the following new sections were added under the "Licenses" heading:

1. Detected an Offline License Version 1, but Version 2 is required

   • Ensure correct key versions are discussed, with explicit instructions to confirm the necessity for updating to a version 2 offline key.

2. Invalid Machine ID Format

   • The text should clarify the need to verify the offline key type according to the specific version requirements of the Vaadin software.

3. Invalid Offline Key

   • The section explains possible errors with offline keys, but an explicit step-by-step guidance on resolving these potential errors would improve clarity and user support.

Overall, clarify instructions for verifying and downloading the correct license keys, with consistent and detailed guidance on troubleshooting and resolution paths.