Don't continue loop for paused sketches

[MartinParrish]

Resolves n/a

Changes:

• Updated saveGif to respect the animation’s paused (noLoop) state if it is paused when saveGif is called, preventing it from automatically resuming.

• This update is similar to the existing handling of pixel density preservation:

const lastPixelDensity = this._pixelDensity;

Motivation: In resource-intensive sketches where noLoop is used, saveGif previously restarted the loop, leading to unnecessary slowdowns during the "Rendering" stage.

Screenshots of the change:

PR Checklist

• npm run lint passes
• Inline documentation is included / updated
• Unit tests are included / updated

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