Update host.json schema for functions extension bundle default

[manvkaur]

This pull request updates the extensionBundle configuration in the host.json schema to reflect newer version ranges and provide clearer documentation. The main focus is on aligning the schema with the latest supported extension bundle versions and improving the description for better clarity.

Schema documentation and version updates:

• Updated the extensionBundle property description to clarify that it refers to a predefined set of compatible binding extensions for a function app.
• Changed the example and default values for the extensionBundle.version property to use the new version range [4.*, 5.0.0) and updated examples to include both the standard and preview extension bundles.
• Updated the example usage of extensionBundle in the schema to use the [4.*, 5.0.0) version range.

[github-actions]

Thanks for the PR!

This section of the codebase is owned by @madskristensen and @hyperupcall - if they write a comment saying "LGTM" then it will be merged.