Frame time widget won't stay still when using a custom editor font

[passivestar]

Tested versions

v4.3.dev6.official [89850d5]

System information

Godot v4.3.dev6 - macOS 14.4.1 - Vulkan (Forward+) - integrated Apple M1 Max - Apple M1 Max (10 Threads)

Issue description

FrameTime.mp4

Doesn't look great because it's flickering even though the number of digits doesn't change. Maybe it needs a minimum width or something like that (Or it could use the monospace font)

Steps to reproduce

Use the Inter font

Minimal reproduction project (MRP)

N/A