fix: Warnings about missing theme/style handlers being printed on launch

lib/libimhex/source/api/theme_manager.cpp

@@ -122,7 +122,7 @@ namespace hex {
             }
         }
 
-        if (theme.contains("colors")) {
+        if (theme.contains("colors") && !s_themeHandlers.empty()) {
             for (const auto&[type, content] : theme["colors"].items()) {
                 if (!s_themeHandlers.contains(type)) {
                     log::warn("No theme handler found for '{}'", type);
@@ -147,7 +147,7 @@ namespace hex {
             }
         }
 
-        if (theme.contains("styles")) {
+        if (theme.contains("styles") && !s_styleHandlers.empty()) {
             for (const auto&[type, content] : theme["styles"].items()) {
                 if (!s_styleHandlers.contains(type)) {
                     log::warn("No style handler found for '{}'", type);

plugins/builtin/source/content/themes.cpp

@@ -8,7 +8,6 @@
 #include <TextEditor.h>
 #include <romfs/romfs.hpp>
 
-#include <hex/helpers/utils.hpp>
 #include <hex/helpers/fs.hpp>
 
 #include <hex/api/event.hpp>