Rewrite the MSAA/UIA integration into conhost (#19344)

Goal: Remove `CursorBlinker`.
Problem: Spooky action at a distance via `Cursor::HasMoved`.
Solution: Moved all the a11y event raising into `_stream.cpp` and pray
for the best.

Goal: Prevent node.js from tanking conhost performance via MSAA (WHY).
Problem: `ServiceLocator`.
Solution: Unserviced the locator. Debounced event raising. Performance
increased by >10x.
Problem 2: Lots of files changed.

This PR is a prerequisite for #19330

## Validation Steps Performed
Ran NVDA with and without UIA enabled and with different delays. ✅

dep/Console/ntcsrdll.h

@@ -7,9 +7,17 @@ Licensed under the MIT license.
 
 #include <ntcsrmsg.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 NTSTATUS CsrClientCallServer(
     PCSR_API_MSG m,
     PCSR_CAPTURE_HEADER CaptureBuffer OPTIONAL,
     ULONG ApiNumber,
     ULONG ArgLength
 );
+
+#ifdef __cplusplus
+}
+#endif

dep/Console/ntlpcapi.h

@@ -5,6 +5,10 @@ Licensed under the MIT license.
 
 #pragma once
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define OB_FILE_OBJECT_TYPE 1
 
 typedef struct _PORT_MESSAGE {
@@ -124,3 +128,7 @@ NTSTATUS NtAlpcQueryInformationMessage(
     ULONG Length,
     PULONG ReturnLength
 );
+
+#ifdef __cplusplus
+}
+#endif