[clangd] Dont include version string in update tasks

This increases cardinality of span latency metrics. Currently this was
being shown to the user via file status updates as `Running Update (x)` after
this change we'll only display `Running Update`. This also affects logs in case
of a crash, but contents and version number for inputs are printed separately in
that case already.

Differential Revision: https://reviews.llvm.org/D124013