fix(lsp): don't use hl_mode = combine for inlay hints #24276

Problem: `hl_mode` for inlay hints is `combine`, causing bugs like
inlay hints using highlights from the previous character
(#24152, #24068)

Solution: Don't use hl_mode=combine for inlay hints.

runtime/lua/vim/lsp/inlay_hint.lua

@@ -289,7 +289,6 @@ api.nvim_set_decoration_provider(namespace, {
               virt_text_pos = 'inline',
               ephemeral = false,
               virt_text = vt,
-              hl_mode = 'combine',
             })
           end
         end