node: update uiInterface whenever warnings updated

This commit introduces slight behaviour change. Previously, the
GUI status bar would be updated for most warnings, namely
UNKNOWN_NEW_RULES_ACTIVATED, CLOCK_OUT_OF_SYNC and
PRE_RELEASE_TEST_BUILD, but not for LARGE_WORK_INVALID_CHAIN
(and not for FATAL_INTERNAL_ERROR, but that is not really
meaningful).

Fix this by always updating the status bar when the warnings are
changed.

src/node/kernel_notifications.cpp

@@ -29,7 +29,6 @@ using util::ReplaceAll;
 
 static void AlertNotify(const std::string& strMessage)
 {
-    uiInterface.NotifyAlertChanged();
 #if HAVE_SYSTEM
     std::string strCmd = gArgs.GetArg("-alertnotify", "");
     if (strCmd.empty()) return;

src/node/timeoffsets.cpp

@@ -3,7 +3,6 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <logging.h>
-#include <node/interface_ui.h>
 #include <node/timeoffsets.h>
 #include <node/warnings.h>
 #include <sync.h>
@@ -50,7 +49,6 @@ bool TimeOffsets::WarnIfOutOfSync() const
     auto median{std::max(Median(), std::chrono::seconds(std::numeric_limits<int64_t>::min() + 1))};
     if (std::chrono::abs(median) <= WARN_THRESHOLD) {
         node::g_warnings.Unset(node::Warning::CLOCK_OUT_OF_SYNC);
-        uiInterface.NotifyAlertChanged();
         return false;
     }
 
@@ -64,6 +62,5 @@ bool TimeOffsets::WarnIfOutOfSync() const
     ), Ticks<std::chrono::minutes>(WARN_THRESHOLD))};
     LogWarning("%s\n", msg.original);
     node::g_warnings.Set(node::Warning::CLOCK_OUT_OF_SYNC, msg);
-    uiInterface.NotifyAlertChanged();
     return true;
 }

src/node/warnings.cpp

@@ -8,6 +8,7 @@
 #include <node/warnings.h>
 
 #include <common/system.h>
+#include <node/interface_ui.h>
 #include <sync.h>
 #include <univalue.h>
 #include <util/translation.h>
@@ -31,12 +32,15 @@ bool Warnings::Set(warning_type id, bilingual_str message)
 {
     LOCK(m_mutex);
     const auto& [_, inserted]{m_warnings.insert({id, std::move(message)})};
+    if (inserted) uiInterface.NotifyAlertChanged();
     return inserted;
 }
 
 bool Warnings::Unset(warning_type id)
 {
-    return WITH_LOCK(m_mutex, return m_warnings.erase(id));
+    auto success{WITH_LOCK(m_mutex, return m_warnings.erase(id))};
+    if (success) uiInterface.NotifyAlertChanged();
+    return success;
 }
 
 std::vector<bilingual_str> Warnings::GetMessages() const

src/node/warnings.h

@@ -31,7 +31,7 @@ enum class Warning {
  * @brief Manages warning messages within a node.
  *
  * The Warnings class provides mechanisms to set, unset, and retrieve
- * warning messages.
+ * warning messages. It updates the GUI when warnings are changed.
  *
  * This class is designed to be non-copyable to ensure warnings
  * are managed centrally.
@@ -52,7 +52,7 @@ public:
      * @brief Set a warning message. If a warning with the specified
      *        `id` is already active, false is returned and the new
      *        warning is ignored. If `id` does not yet exist, the
-     *        warning is set, and true is returned.
+     *        warning is set, the UI is updated, and true is returned.
      *
      * @param[in]   id  Unique identifier of the warning.
      * @param[in]   message Warning message to be shown.
@@ -63,8 +63,9 @@ public:
     bool Set(warning_type id, bilingual_str message) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
     /**
      * @brief Unset a warning message. If a warning with the specified
-     *        `id` is active, it is unset, and true is returned.
-     *        Otherwise, no warning is unset and false is returned.
+     *        `id` is active, it is unset, the UI is updated, and true
+     *        is returned. Otherwise, no warning is unset and false is
+     *        returned.
      *
      * @param[in]   id  Unique identifier of the warning.
      *