Adopt Polyfill 9.24.0 span-based TryParse for float and decimal

[sliekens]

Polyfill 9.24.0 added 14 new polyfill methods for span-based and UTF-8 parsing of float and decimal values (native in .NET 8+, polyfilled for older TFMs).

New APIs

decimal.TryParse new overloads

• TryParse(string? s, IFormatProvider? provider, out decimal result)
• TryParse(ReadOnlySpan<char> s, out decimal result)
• TryParse(ReadOnlySpan<char> s, IFormatProvider? provider, out decimal result)
• TryParse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider? provider, out decimal result)
• UTF-8 span variants: TryParse(ReadOnlySpan<byte> utf8Text, ...)

float / Single.TryParse new overloads

Identical set of overloads as decimal.

Relevance

GW2SDK uses float and decimal extensively for coordinates and prices, currently parsed via JSON deserialization. If any future parsing code needs to parse numeric values from spans (e.g., HTTP header values or raw byte buffers), these polyfilled overloads can avoid extra allocations on older TFMs.

Investigate whether any parsing code in the library could benefit from these overloads.