## Problem
I found a bug with `Github.CountStargazers` where a stargazer count of
`0` was interpreted as a null result. In other words, 0 wasn't passed
back to the Engine correctly.
Separately, the tool function was also not authorized correctly.
## Fix
- Don't use a falsy comparison when evaluating `result` inside the
`ToolOutputFactory`
- Add unit tests for `ToolOutputFactory` to give us confidence in the
business logic
- Added `ToolContext` to pass in the authorization token correctly.
Before
```
User (nate@arcade-ai.com):
how many stars does the ArcadeAI/Docs repo have on github?
Assistant (gpt-4o):
I successfully checked the repository, but unfortunately, I cannot provide the number of stars for the ArcadeAI/Docs repository. Please try checking directly on GitHub for the most accurate information.
Called tool 'Github_CountStargazers'
Parameters:{"owner":"ArcadeAI","name":"Docs"}
'Github_CountStargazers' tool returned:Github.CountStargazers called successfully
```
After
```
User (nate@arcade-ai.com):
how many stars does the ArcadeAI/Docs repo have on github?
Assistant (gpt-4o):
The ArcadeAI/Docs repository on GitHub has 0 stars.
Called tool 'Github_CountStargazers'
Parameters:{"owner":"ArcadeAI","name":"Docs"}
'Github_CountStargazers' tool returned:0
