### Godot version

4.1.1 stable

### System information

Windows 10

### Issue description

this is the default size loaded on startup 1024 which seems fine but it actually have loaded the default [2048] and ignored the size in project settings
![image](https://github.com/godotengine/godot/assets/53877170/c8c71de7-468a-487f-8e6c-dba1ce0f8fa5)

changing it now to any size will break it 
[2048]
![image](https://github.com/godotengine/godot/assets/53877170/3082ff09-b7d7-41f7-8fbb-813074a54135)

[512]
![image](https://github.com/godotengine/godot/assets/53877170/5ea4620f-52b5-4d0e-a5f5-747e777cd59d)


### Steps to reproduce

change 2d shadow atlas size in project settings while using compatibility renderer. 

### Minimal reproduction project

_
case GLES3::CanvasShaderData::BLEND_MODE_LCD: {
					glBlendEquation(GL_FUNC_ADD);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_CONSTANT_COLOR, GL_ONE_MINUS_SRC_COLOR, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
					} else {
						glBlendFuncSeparate(GL_CONSTANT_COLOR, GL_ONE_MINUS_SRC_COLOR, GL_ZERO, GL_ONE);
					}
					glBlendColor(blend_color.r, blend_color.g, blend_color.b, blend_color.a);
				} break;
				case GLES3::CanvasShaderData::BLEND_MODE_MIX: {
					glBlendEquation(GL_FUNC_ADD);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
					} else {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ZERO, GL_ONE);
					}
				} break;
				case GLES3::CanvasShaderData::BLEND_MODE_ADD: {
					glBlendEquation(GL_FUNC_ADD);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_SRC_ALPHA, GL_ONE);
					} else {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_ZERO, GL_ONE);
					}
				} break;
				case GLES3::CanvasShaderData::BLEND_MODE_SUB: {
					glBlendEquation(GL_FUNC_REVERSE_SUBTRACT);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_SRC_ALPHA, GL_ONE);
					} else {