Add array of toolNames to CreatePromptRequest

[MaesterChestnut]

Adding the toolNames property to CreatePromptRequestSchema which will then get passed to the PromptFormatter used to export prompts from the Prompt Runner and Model Runner. I used the property toolNames instead of tools to prevent incompatibility with the main branch of the genkit-ui which sends tools as a ToolDefinitionSchema object.

Checklist (if applicable):

• Tested (manually, unit tested, etc.)
  Manually tested without UI changes to ensure this is a non-breaking change
• Changelog updated
• Docs updated