refactor: Make MessageBoxFlags enum underlying type unsigned

src/node/ui_interface.h

@@ -25,8 +25,7 @@ class CClientUIInterface
 {
 public:
     /** Flags for CClientUIInterface::ThreadSafeMessageBox */
-    enum MessageBoxFlags
-    {
+    enum MessageBoxFlags : uint32_t {
         ICON_INFORMATION    = 0,
         ICON_WARNING        = (1U << 0),
         ICON_ERROR          = (1U << 1),

test/sanitizer_suppressions/ubsan

@@ -66,7 +66,6 @@ implicit-integer-sign-change:compat/stdin.cpp
 implicit-integer-sign-change:compressor.h
 implicit-integer-sign-change:crypto/
 implicit-integer-sign-change:key.cpp
-implicit-integer-sign-change:noui.cpp
 implicit-integer-sign-change:policy/fees.cpp
 implicit-integer-sign-change:prevector.h
 implicit-integer-sign-change:script/bitcoinconsensus.cpp