docs(mcp): add Gemini Enterprise connection guide - #461

Running Vale across on the following files affected by this PR:

- product/admin/mcp-server/gemini-enterprise.mdx

Attempting to initialize Vale linter...
No customer vale configuration detected. Using Mintlify's default configuration.
Attempting to run Vale spellcheck...
Vale spellcheck completed successfully.

product/admin/mcp-server/gemini-enterprise.mdx:
	- 14:176     Did you really mean 'walkthrough'?
	- 36:155     Did you really mean 'toolset'?
	- 192:28     Did you really mean 'hostnames'?
	- 201:27     Did you really mean 'hostnames'?
	- 201:128    Did you really mean 'hostnames'?
	- 330:211    Did you really mean 'toolset'?
	- 348:179    Did you really mean 'eu'?
	- 364:93     Did you really mean 'toolset'?
	- 368:125    Did you really mean 'hostname'?


Found 9 suggested changes across 1 files in 5425.45ms