Encrypted metadata does not work

[mkleene]

If encrypted metadata is included in the manifest we get a base64 decoding exception during decryption:

java.lang.IllegalArgumentException: Illegal base64 character 7b

	at java.base/java.util.Base64$Decoder.decode0(Base64.java:746)
	at java.base/java.util.Base64$Decoder.decode(Base64.java:538)
	at java.base/java.util.Base64$Decoder.decode(Base64.java:561)
	at io.opentdf.platform.sdk.TDF$Reader.doPayloadKeyUnwrap(TDF.java:238)
	at io.opentdf.platform.sdk.TDF.loadTDF(TDF.java:429)
	at io.opentdf.platform.sdk.TDFTest.testSimpleTDFEncryptAndDecrypt(TDFTest.java:71)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)

[mkleene]

fixed by #64