Allow log_shiny_input_changes to have different init level

[taekeharkema]

Hi,

I wanted to use logger::log_shiny_input_changes in a Shiny-app we're building, but was bothered by the fact that the default shiny-inputs are logged at a static INFO-level. It would be nice if that was flexible. The current PR simply takes the level of the level argument provided by log_shiny_input_changes instead.

Is this something you'd be willing to consider?

I added some tests, but they rely on internal structure of the Shiny-package, as the function checks whether the shiny app isRunning(), and apparently and unfortunately it is not within a testServer.

[daroczig]

Sorry that I overlooked this contribution for so long time -- this is awesome, thanks!! 🙇