Remove duplicate ucaps code from TextServerFallback.

modules/text_server_fb/text_server_fb.cpp

@@ -51,7 +51,6 @@ using namespace godot;
 #include "core/error/error_macros.h"
 #include "core/string/print_string.h"
 #include "core/string/translation.h"
-#include "core/string/ucaps.h"
 
 #include "modules/modules_enabled.gen.h" // For freetype, msdfgen, svg.
 
@@ -4060,31 +4059,11 @@ double TextServerFallback::_shaped_text_get_underline_thickness(const RID &p_sha
 }
 
 String TextServerFallback::_string_to_upper(const String &p_string, const String &p_language) const {
-	String upper = p_string;
-
-	for (int i = 0; i <= upper.length(); i++) {
-		const char32_t s = upper[i];
-		const char32_t t = _find_upper(s);
-		if (s != t) { // avoid copy on write
-			upper[i] = t;
-		}
-	}
-
-	return upper;
+	return p_string.to_upper();
 }
 
 String TextServerFallback::_string_to_lower(const String &p_string, const String &p_language) const {
-	String lower = p_string;
-
-	for (int i = 0; i <= lower.length(); i++) {
-		const char32_t s = lower[i];
-		const char32_t t = _find_lower(s);
-		if (s != t) { // avoid copy on write
-			lower[i] = t;
-		}
-	}
-
-	return lower;
+	return p_string.to_lower();
 }
 
 PackedInt32Array TextServerFallback::_string_get_word_breaks(const String &p_string, const String &p_language, int p_chars_per_line) const {