⚡ Remove redundant path.move in polyline snapshot loop

[esenmx]

💡 What:
Removed the redundant path.move(to: snapshot.point(for: coordinate)) call inside the polyline point iteration loop in FlutterPolyline.swift and updated the iteration to use coordinates.dropFirst().

🎯 Why:
path.addLine(to:) in UIBezierPath automatically updates the current point of the path. Calling move(to:) after every segment creates a new subpath for each segment, doubling snapshot.point(for:) lookups per point (from $N$ to $2N$), increasing memory overhead, and breaking line joins across polyline segments.

📊 Measured Improvement:
Direct execution of native Swift benchmarks is not supported in the Linux sandbox environment. However, algorithmically:

• Snapshot point conversions per polyline segment decrease from $2N$ to $N$.
• Subpath allocations decrease from $N-1$ subpaths to $1$ contiguous subpath per polyline.
• Line joins and stroke caps now render correctly as a single joined path.

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PR created automatically by Jules for task 13544136725387948932 started by @esenmx

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