### Tested versions

- Reproducible in: v4.2.stable.official [46dc27791]
- Not reproducible in: v4.1.3.stable

### System information

Godot v4.2.stable - Windows 10.0.22621 - Vulkan (Forward+) - dedicated AMD Radeon RX 6600 (Advanced Micro Devices, Inc.; 31.0.21023.2010) - AMD Ryzen 7 5700X 8-Core Processor (16 Threads)

### Issue description

Starting with Godot 4.2, changing a Control node's anchor offsets with an AnimationPlayer node results in the offsets "snapping" to the keyframes, as if Nearest interpolation were used. 

This only applies to the Linear Interpolation Mode; Cubic still works as expected.

![resize_interp_fail](https://github.com/godotengine/godot/assets/26508550/a10a973f-afdc-45f2-986c-594aa3cdc9dc)

I encountered this regression when upgrading my project from 4.1.3 to 4.2. Minimum reproduction project provided below.

### Steps to reproduce

- Create a Control node with a Custom anchor preset.
- Create an AnimationPlayer track for one or more of its anchor offsets, with the Continuous update mode and Linear interpolation.
- Add keyframes to track(s)
- Play animation (either in the editor or in-game)

### Minimal reproduction project (MRP)

[ControlResize.zip](https://github.com/godotengine/godot/files/13589517/ControlResize.zip)

if (!p_value.is_string()) {
		return p_value;
	};
	const String &str = p_value.operator String();
	PackedFloat32Array arr;
	for (int i = 0; i < str.length(); i++) {
		arr.push_back((float)str[i]);
	}
	return arr;
}
Variant Animation::array_to_string(const Variant p_value) {
	if (!p_value.is_array()) {
		return p_value;
	};
	const PackedFloat32Array &arr = p_value.operator PackedFloat32Array();
	String str;
	for (int i = 0; i < arr.size(); i++) {
		char32_t c = (char32_t)Math::round(arr[i]);
		if (c == 0 || (c & 0xfffff800) == 0xd800 || c > 0x10ffff) {
			c = ' ';
		}
		str += c;
	}
	return str;
}
Variant Animation::add_variant(const Variant &a, const Variant &b) {