Handling ".uno:InsertSymbol?Symbols:string=" appears to be dead code

4d3148e0b7ee607de9c86e9e9aa79e9cd423f1f1 "CWS-TOOLING: integrate CWS
mba32issues01" had introduced it, along with code in
SfxConfigGroupListBox_Impl::AddAndSelect to generate such URLs, but which had
been commented out from the beginning (and since been removed), and all other
places that mention .uno:InsertSymbol apparently use it without a query part (to
run the special character dialog), and the string has 33 characters, not 34, so
aRet would not contain the first character after Symbols:string=, which looks
odd.

Change-Id: Icdab24148b217531f2db65b1604678650180a22c