Remove GetGraph and include of Graph.hpp header from public header

Remove deprecated GetGraph() from OptimizationViews. This method has
been deprecated for a long time and no backends still need it. Remove
include of Graph.hpp from the public headers.

Add includes elsewhere to deal with the header fallout.

Signed-off-by: Matthew Bentham <matthew.bentham@arm.com>
Change-Id: I8dae275a8a446d9d0e19be62684e9b3cd2fa493d
diff --git a/src/backends/neon/test/NeonBackendTests.cpp b/src/backends/neon/test/NeonBackendTests.cpp
index 23f58a7..562a45e 100644
--- a/src/backends/neon/test/NeonBackendTests.cpp
+++ b/src/backends/neon/test/NeonBackendTests.cpp
@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: MIT
 //
 
+#include <backendsCommon/TensorHandleFactoryRegistry.hpp>
 #include <neon/NeonBackend.hpp>
 #include <neon/NeonTensorHandleFactory.hpp>