This fixes issues where subsequent calls to vim.lsp.codelens.refresh()
would have no effect due to the buffer not getting cleared from the
active_refresh table.
Examples of how such scenarios would occur are:
- A textDocument/codeLens result yielded an error.
- The 'textDocument/codeLens' handler was overriden in such a way that
it no longer called vim.lsp.codelens.on_codelens().
(cherry picked from commit 94eb72cc44)