Use byte arrays for SOAP hex parses with a silent fallback

Replace closed SoapHexBinary.Parse locals used only through Value inside a direct try body with byte arrays and a Convert.FromHexString helper. Require one bare, unfiltered catch returning a literal or default and no finally. Preserve Framework space/CR/LF filtering, fresh empty arrays, argument evaluation and the existing fallback. Exceptions observed by a caller, typed catch, filter, log or rethrow remain for review. Targets .NET 5+.