Fix incorrect usage of github.event

[CISC]

Discovered this while debugging #7034

Warning: This may change current behavior as all these evaluated to null before!

[CISC]

I just noticed github.event.inputs is part of workflow_dispatch payload, so not technically incorrect after all, but unnecessarily long at least. Also has this difference:

The workflow will also receive the inputs in the github.event.inputs context. The information in the inputs context and github.event.inputs context is identical except that the inputs context preserves Boolean values as Booleans instead of converting them to strings. The choice type resolves to a string and is a single selectable option.

Additionally I can see that github.event.schedule is also defined even though it's apparently not documented:

##[debug]..Evaluating success:
##[debug]..=> true
##[debug]..Evaluating Or:
##[debug]....Evaluating Index:
##[debug]......Evaluating Index:
##[debug]........Evaluating github:
##[debug]........=> Object
##[debug]........Evaluating String:
##[debug]........=> 'event'
##[debug]......=> Object
##[debug]......Evaluating String:
##[debug]......=> 'schedule'
##[debug]....=> '2 4 * * *'
##[debug]..=> '2 4 * * *'