### Godot version

4.0.beta16

### System information

Windows 10 Pro x64, GLES3, RTX 3080 Ti (528.02)

### Issue description

In Compatibility/GLES3 back-end, shaders which use a uniform to get the normal roughness buffer cannot compile. For example, the shader:
```glsl
shader_type spatial;

uniform sampler2D normal_roughness_texture : hint_normal_roughness_texture;

void fragment() {
    vec4 sample = texture(normal_roughness_texture, UV);
}
```
results in an error in the output:
```
  drivers/gles3/shader_gles3.cpp:242 - SceneShaderGLES3: Fragment shader compilation failed:
  0(890) : error C1503: undefined variable "normal_roughness_buffer"
  
  drivers/gles3/shader_gles3.cpp:342 - Method/function failed.
```

If I switch over to the Mobile or Forward+ backends, there is no shader compilation error.

### Steps to reproduce

Open the attached reproduction in the 4.0.beta16 editor.

When the scene is opened, the error is produced automatically:
1. Open `scene.tscn`
2. Open Output to review error

When the scene is saved with any changes made to the shader, the same error is also produced:
1. Open `scene.tscn`
2. Open `example.gdshader` in the shader editor.
3. Make a compile-able change to the shader.
4. Save the scene
5. Open Output to review the error

### Minimal reproduction project

[NormalRoughnessTexture_GLES3_Error.zip](https://github.com/godotengine/godot/files/10534253/NormalRoughnessTexture_GLES3_Error.zip)

is_const_suffix_lut_initialized = true;
						for (int i = 0; i < 127; i++) {
							char t = char(i);
							suffix_lut[CASE_ALL][i] = t == '.' || t == 'x' || t == 'e' || t == 'f' || t == 'u' || t == '-' || t == '+';
							suffix_lut[CASE_HEXA_PERIOD][i] = t == 'e' || t == 'f';
							suffix_lut[CASE_EXPONENT][i] = t == 'f' || t == '-' || t == '+';
							suffix_lut[CASE_SIGN_AFTER_EXPONENT][i] = t == 'f';
							suffix_lut[CASE_NONE][i] = false;
						}
					}
					String str;
					int i = 0;
					bool digit_after_exp = false;
					while (true) {
						const char32_t symbol = String::char_lowercase(GETCHAR(i));
						bool error = false;
						if (is_digit(symbol)) {
							if (exponent_found) {
								digit_after_exp = true;
							}
							if (end_suffix_found) {
								error = true;
							}
						} else {
							if (symbol < 0x7F && suffix_lut[lut_case][symbol]) {
								if (symbol == 'x') {
									hexa_found = true;
									lut_case = CASE_HEXA_PERIOD;
								} else if (symbol == '.') {
									period_found = true;