Revert "project: Handle textDocument/didSave and textDocument/didChange (un)registration and usage correctly (#36441)" (#36480)

This reverts commit c5991e74bb.

This PR broke rust-analyzer's check on save function, so reverting for
now

Release Notes:

- N/A

crates/lsp/src/lsp.rs

@@ -827,7 +827,7 @@ impl LanguageServer {
                     }),
                     synchronization: Some(TextDocumentSyncClientCapabilities {
                         did_save: Some(true),
-                        dynamic_registration: Some(true),
+                        dynamic_registration: Some(false),
                         ..TextDocumentSyncClientCapabilities::default()
                     }),
                     code_lens: Some(CodeLensClientCapabilities {