Fix chat scale loading and precision

[HeresHavi]

Summary

Fixed Chat Scale loading the first stored value into both X and Y.

Both values now load independently and keep their saved precision.

Motivation

The settings loader rounded the first scale value to one decimal place and used it for both fields. This changed non-uniform chat scales whenever the settings were loaded and saved.

For example, the bundled Race Oversized preset uses 1.65 × 1.17. The old loader changed it to 1.6 × 1.6, losing both the separate Y value and the original precision.

Fixes #5035.

Test plan

Runtime

• Before Fix: A stored value of 1.65 1.17 loaded and saved as 1.6 × 1.6.
• After Fix: The same value loaded as 1.65 × 1.17 and survived saving and restarting MTA.
• Presets: Confirmed Race Oversized and iRace 2009 loaded their separate X and Y values.
• Valid Range: Confirmed both values still clamp independently to the existing 0.5 to 3 range.
• Defaults: Removing the setting recreated the default 1 × 1 scale.
• Live Update: Applied opposite non-uniform values and confirmed they changed the live chat immediately and remained saved.

Builds and Tests

• Debug | Win32: Client Core build passed, 304 client tests passed.
• Release | Win32: Client Core build passed, 304 client tests passed.

Checklist

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