fix: MIME Decoding corrupts non-ASCII characters in Base64-encoded words#2291
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fromBase64() defaults to returning a UTF-8 decoded string, which is then passed to codepage.utils.decode() that treats each char code as a raw byte. For multi-byte UTF-8 characters, this double-decoding produces garbage (e.g. "café" becomes "caf退"). Pass returnType="byteArray" so codepage receives raw bytes and performs the single correct UTF-8 decode. Closes gchq#2280
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fromBase64() defaults to returning a UTF-8 decoded string, which is then passed to codepage.utils.decode() that treats each char code as a raw byte.
For multi-byte UTF-8 characters, this double-decoding produces garbage (e.g. "café" becomes "caf退").
Pass returnType="byteArray" so codepage receives raw bytes and performs the single correct UTF-8 decode.
Closes #2280
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