Remove outdated timestamp for Dash assets

[rpkyle]

Dash for R still retains ?v= and &m= within utils.R, when serving fingerprinted assets via the _dash-component-suites handler: https://github.com/plotly/dashR/blob/9c5a30760e3be985c866f122e9c2bd6ce2a516a6/R/utils.R#L167-L182

This has since been eliminated in Dash for Python. For the sake of parity, it should be excised from Dash for R also.

@Marc-Andre-Rivet

[alexcjohnson]

FYI we still do use ?m= in dash Py for assets including favicon - I guess because we didn't get around to or couldn't figure out how to incorporate the cache-busting hash into the filename for items we're serving via flask.Blueprint

Shouldn't stop us from getting rid of all the query params on the R side since we're already parsing those urls ourselves but note that regex will need to change.