Misc: Use compareNoCase instead of Strncasecmp

Strncasecmp("a", "ab", 1) returns true, which isn't what we want

common/Image.cpp

@@ -55,7 +55,7 @@ static const FormatHandler* GetFormatHandler(const std::string_view extension)
 {
 	for (const FormatHandler& handler : s_format_handlers)
 	{
-		if (StringUtil::Strncasecmp(extension.data(), handler.extension, extension.size()) == 0)
+		if (StringUtil::compareNoCase(extension, handler.extension))
 			return &handler;
 	}
 

pcsx2/GS/Renderers/HW/GSTextureReplacementLoaders.cpp

@@ -36,7 +36,7 @@ GSTextureReplacements::ReplacementTextureLoader GSTextureReplacements::GetLoader
 
 	for (const LoaderDefinition& defn : s_loaders)
 	{
-		if (StringUtil::Strncasecmp(extension.data(), defn.extension, extension.size()) == 0)
+		if (StringUtil::compareNoCase(extension, defn.extension))
 			return defn.loader;
 	}
 

pcsx2/GS/Renderers/HW/GSTextureReplacements.cpp

@@ -451,7 +451,7 @@ void GSTextureReplacements::ReloadReplacementMap()
 		// file format we can handle?
 		const char* filename = Path::GetFileName(fd.FileName).data(); // GetFileName takes a substring from the end, so the null terminator is preserved
 		std::string_view ext = Path::GetExtension(filename);
-		if (ext.size() == 3 && 0 == StringUtil::Strncasecmp(ext.data(), "zip", 3))
+		if (StringUtil::compareNoCase(ext, "zip"))
 		{
 			zip_error_t ze = {};
 			auto zf = zip_open_managed(fd.FileName.c_str(), ZIP_RDONLY, &ze);