Issue Description

On Android API 26+, @nativescript/core loads custom font files through android.graphics.Typeface.Builder and passes font-variation-settings via setFontVariationSettings. For a variable font, the font-weight CSS property has no effect unless the caller also knows to pass an explicit 'wght' variation setting: loadFontFromFile never maps fontWeight onto the wght axis, so e.g. font-family: 'MyVariableFont'; font-weight: 700 renders at the font's default weight.

Two adjacent problems:

• computeFontCacheKey keys the typeface cache only on family + explicit variation settings, so once the weight is forwarded (by workaround or fix), two weights of the same family collide in the cache.
• If a font doesn't support the wght axis, builder.build() throws and there is no retry — the file load fails outright instead of falling back to the explicit variation settings.

Reproduction

On an API 26+ Android device/emulator with a variable font (e.g. fonts/Inter.var.ttf):

<Label fontFamily="Inter.var" fontWeight="700" text="should be bold" />

The label renders at the font's default weight (400) because setFontVariationSettings is called with '' (no wght axis).

Proposed fix

In loadFontFromFile, inject { axis: 'wght', value: <numeric fontWeight> } into the variation settings when the caller did not set wght explicitly, include fontWeight in computeFontCacheKey, and retry the build with the caller's explicit settings if the wght-augmented build throws.

Environment

• @nativescript/core 9.x, Android API 26+

I have a PR with this fix plus unit tests ready to submit.