fix(lsp): announce publishDiagnostics.dataSupport (#24442)

Neovim already passed `data` element from published diagnostic to code action, but failed to announce it in client capabilities.

Here is the test that shows that `data` element is returned by `vim.lsp.diagnostic.get_line_diagnostics()`:

f56c184809/test/functional/plugin/lsp/diagnostic_spec.lua (L103-L115)

and then `get_line_diagnostics()` is used to construct the context for code action request:

f56c184809/runtime/lua/vim/lsp/buf.lua (L742)

runtime/lua/vim/lsp/protocol.lua

@@ -828,6 +828,7 @@ function protocol.make_client_capabilities()
             return res
           end)(),
         },
+        dataSupport = true,
       },
       callHierarchy = {
         dynamicRegistration = false,