Tearing when using UV to access an array of sampler2d's

### Tested versions

Reproducible in: 4.3stable and 4.4dev3

### System information

Godot v4.3.stable - Windows 10.0.26100 - Vulkan (Forward+) - dedicated AMD Radeon RX 6600 (Advanced Micro Devices, Inc.; 32.0.12011.1036) - 12th Gen Intel(R) Core(TM) i3-12100F (8 Threads)

### Issue description

I wrote a short shader to have a mesh sample one image when UV.x < 0.5, and another image otherwise.
Here it is:
```
shader_type spatial;
uniform sampler2D[2] images : source_color;

void fragment() {
ALBEDO = texture(images[int(step(0.5, UV.x))], UV).rgb;
}
```

But when you put it on a mesh and fill the array with two different images it looks something like this:

I expected a clean line in the middle separating the two images, like this:

The code for the above:
```
shader_type spatial;
uniform sampler2D[2] images : source_color;

vec3 get_color(int index, vec2 uv) {
if(index == 1) {
return texture(images[1], uv).rgb;
}
return texture(images[0], uv).rgb;
}
void fragment() {
ALBEDO = get_color(int(step(0.5, UV.x)), UV);
}
```

### Steps to reproduce

After you open the MRP, the issue should be visible immediately.

### Minimal reproduction project (MRP)

[MRP_bug.zip](https://github.com/user-attachments/files/17430209/MRP_bug.zip)

Open MRP_bug.zip and reproduce the artifact using the first shader with the sampler2d array, then compare it with the helper-function shader shown in the report. Confirm the behavior on the reported Godot versions and Vulkan setup; done means the two images meet at a clean line without tearing.

Written by the indexing model from the issue text.