fix(go/genkit): Fix input from context

[rutujaD1999]

ISSUES:
[ ] [https://github.com//issues/2419 ]

CHANGELOG:
[ ] Modified the sample to include input data from action context with @
[ ] Updated to latest version of dotprompt with the fix for handling context inputs

Checklist (if applicable):

• PR title is following https://www.conventionalcommits.org/en/v1.0.0/
• Tested (manually, unit tested, etc.)
• Docs updated (updated docs or a docs bug required)