Remove outdated timestamp for Dash assets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:

dashR/R/utils.R

Lines 167 to 182 in 9c5a307

	if ("script" %in% names(dep) && tools::file_ext(dep[["script"]]) != "map") {
	if (!(is_local) & !(is.null(dep$src$href))) {
	html <- generate_js_dist_html(href = dep$src$href)
	} else {
	script_mtime <- file.mtime(getDependencyPath(dep))
	modtime <- as.integer(script_mtime)
	dep$script <- buildFingerprint(dep$script, dep$version, modtime)
	dep[["script"]] <- paste0(path_prefix,
	"_dash-component-suites/",
	dep$name,
	"/",
	basename(dep[["script"]]),
	"?v=",
	dep$version,
	"&m=",
	modified)

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.