Give LineEdit a custom font color when un-editable

By default the LineEdit's text when editable is unchecked had some transparency hardcoded.
This change adds a custom color to LineEdit for adjusting the font when editable is off.
Addresses issue 29814

scene/gui/line_edit.cpp

@@ -675,10 +675,8 @@ void LineEdit::_notification(int p_what) {
 			RID ci = get_canvas_item();
 
 			Ref<StyleBox> style = get_stylebox("normal");
-			float disabled_alpha = 1.0; // used to set the disabled input text color
 			if (!is_editable()) {
 				style = get_stylebox("read_only");
-				disabled_alpha = .5;
 				draw_caret = false;
 			}
 
@@ -724,7 +722,7 @@ void LineEdit::_notification(int p_what) {
 			int font_ascent = font->get_ascent();
 
 			Color selection_color = get_color("selection_color");
-			Color font_color = get_color("font_color");
+			Color font_color = is_editable() ? get_color("font_color") : get_color("font_color_uneditable");
 			Color font_color_selected = get_color("font_color_selected");
 			Color cursor_color = get_color("cursor_color");
 
@@ -732,12 +730,11 @@ void LineEdit::_notification(int p_what) {
 			// draw placeholder color
 			if (using_placeholder)
 				font_color.a *= placeholder_alpha;
-			font_color.a *= disabled_alpha;
 
 			bool display_clear_icon = !using_placeholder && is_editable() && clear_button_enabled;
 			if (right_icon.is_valid() || display_clear_icon) {
 				Ref<Texture> r_icon = display_clear_icon ? Control::get_icon("clear") : right_icon;
-				Color color_icon(1, 1, 1, disabled_alpha * .9);
+				Color color_icon(1, 1, 1, !is_editable() ? .5 * .9 : .9);
 				if (display_clear_icon) {
 					if (clear_button_status.press_attempt && clear_button_status.pressing_inside) {
 						color_icon = get_color("clear_button_color_pressed");

scene/resources/default_theme/default_theme.cpp

@@ -398,6 +398,7 @@ void fill_default_theme(Ref<Theme> &theme, const Ref<Font> &default_font, const
 
 	theme->set_color("font_color", "LineEdit", control_font_color);
 	theme->set_color("font_color_selected", "LineEdit", Color(0, 0, 0));
+	theme->set_color("font_color_uneditable", "LineEdit", Color(control_font_color.r, control_font_color.g, control_font_color.b, 0.5f));
 	theme->set_color("cursor_color", "LineEdit", control_font_color_hover);
 	theme->set_color("selection_color", "LineEdit", font_color_selection);
 	theme->set_color("clear_button_color", "LineEdit", control_font_color);