isBase32 function
Checks if the string is base32 encoded.
Base32 encoding uses a 32-character set (A-Z and 2-7) to represent binary data. Valid base32 strings may include padding with '=' characters.
Returns true if the string is valid base32 encoded, otherwise returns false.
Example:
isBase32('JBSWY3DPEHPK3PXP'); // true
isBase32('hello world'); // false
Implementation
bool isBase32(String str) => _isBase32(str);