[.NET] Update required .NET SDK version in error messages

Also, replaces the download URL with a shorter one since links are not clickable so I thought it'd be more convenient.

modules/mono/mono_gd/gd_mono.cpp

@@ -363,7 +363,7 @@ godot_plugins_initialize_fn initialize_hostfxr_and_godot_plugins(bool &r_runtime
 
 	if (load_assembly_and_get_function_pointer == nullptr) {
 		// Show a message box to the user to make the problem explicit (and explain a potential crash).
-		OS::get_singleton()->alert(TTR("Unable to load .NET runtime, no compatible version was found.\nAttempting to create/edit a project will lead to a crash.\n\nPlease install the .NET SDK 6.0 or later from https://dotnet.microsoft.com/en-us/download and restart Godot."), TTR("Failed to load .NET runtime"));
+		OS::get_singleton()->alert(TTR("Unable to load .NET runtime, no compatible version was found.\nAttempting to create/edit a project will lead to a crash.\n\nPlease install the .NET SDK 8.0 or later from https://get.dot.net and restart Godot."), TTR("Failed to load .NET runtime"));
 		ERR_FAIL_V_MSG(nullptr, ".NET: Failed to load compatible .NET runtime");
 	}
 
@@ -551,7 +551,7 @@ void GDMono::initialize() {
 #else
 
 		// Show a message box to the user to make the problem explicit (and explain a potential crash).
-		OS::get_singleton()->alert(TTR("Unable to load .NET runtime, specifically hostfxr.\nAttempting to create/edit a project will lead to a crash.\n\nPlease install the .NET SDK 6.0 or later from https://dotnet.microsoft.com/en-us/download and restart Godot."), TTR("Failed to load .NET runtime"));
+		OS::get_singleton()->alert(TTR("Unable to load .NET runtime, specifically hostfxr.\nAttempting to create/edit a project will lead to a crash.\n\nPlease install the .NET SDK 8.0 or later from https://get.dot.net and restart Godot."), TTR("Failed to load .NET runtime"));
 		ERR_FAIL_MSG(".NET: Failed to load hostfxr");
 #endif
 	}