Add missing check when insert function normal_roughness_compatibility

[jsjtxietian]

Fixes #87202

Without this check, the shader ivec2 normal_roughness_size = textureSize(normal_roughness_buffer, 0); compiles to
ivec2 m_normal_roughness_size=normal_roughness_compatibility(textureSize(sampler2D(normal_roughness_buffer, SAMPLER_LINEAR_WITH_MIPMAPS_REPEAT), 0)); and thus type mismatch and compile error.

Introduced in #86316 , cc @clayjohn Any suggestions?

[danbolt]

Hi, thanks for the quick turnaround!

I just compiled Godot at 26b1fd0 with this change and it addressed the issue I was encountering with #87202. 👍

[clayjohn]

Good catch!

This is the correct fix. Great work

[akien-mga]

Thanks!