[clangd] Fix -check mode doesn't respect any tidy configs.

[hokein]

no test added -- it is not easy, since we don't emit tidy warnings in check mode (maybe we should?), I confirmed that it worked (with manual test).

clang-tools-extra/clangd/tool/Check.cpp

public:
 
   // Prepare inputs and build CompilerInvocation (parsed compile command).
   bool buildInvocation(const ThreadsafeFS &TFS,
                        llvm::Optional<std::string> Contents) {
     StoreDiags CaptureInvocationDiags;
     std::vector<std::string> CC1Args;
     Inputs.CompileCommand = Cmd;
     Inputs.TFS = &TFS;
+    Inputs.ClangTidyProvider = Opts.ClangTidyProvider;
     if (Contents.hasValue()) {
       Inputs.Contents = *Contents;
       log("Imaginary source file contents:\n{0}", Inputs.Contents);
     } else {
       if (auto Contents = TFS.view(llvm::None)->getBufferForFile(File)) {
         Inputs.Contents = Contents->get()->getBuffer().str();
       } else {
         elog("Couldn't read {0}: {1}", File, Contents.getError().message());