Title on y-axis isn't centered in locales other than English

[Nancy-Salpepi]

Test device
MacBook Air M1 chip and Chromebook

Operating System
macOS14.5

Browser
Safari + Chrome

Problem description
For phetsims/qa#1100, on the Energy Screen:
In locales other than English the "Number of Particles" title on the y-axis for both graphs isn't centered. The title on the x-axis is always centered no matter which locale is selected.

Visuals

It is very easy to see using ?stringTest=dynamic:

[pixelzoom]

@Nancy-Salpepi please review, close if OK.

[Nancy-Salpepi]

Looks good now. Closing.