Check recovery password is hex if its not a mnemonic

libsignal/src/main/java/org/session/libsignal/crypto/MnemonicCodec.kt

@@ -1,6 +1,7 @@
 package org.session.libsignal.crypto
 
 import org.session.libsignal.utilities.Hex
+import org.session.libsignal.utilities.isHex
 import java.util.zip.CRC32
 
 /**
@@ -126,6 +127,7 @@ class MnemonicCodec(private val loadFileContents: (String) -> String) {
     fun decodeMnemonicOrHexAsByteArray(mnemonicOrHex: String): ByteArray = try {
         decode(mnemonic = mnemonicOrHex).let(Hex::fromStringCondensed)
     } catch (decodeException: Exception) {
+        if (mnemonicOrHex.isHex()) throw decodeException
         try {
             Hex.fromStringCondensed(mnemonicOrHex)
         } catch (_: Exception) {

libsignal/src/main/java/org/session/libsignal/utilities/Hex.kt

@@ -0,0 +1,9 @@
+package org.session.libsignal.utilities
+
+private val HEX_CHARS = buildSet {
+    addAll('0'..'9')
+    addAll('a'..'f')
+    addAll('A'..'F')
+}
+
+fun String.isHex() = all { it in HEX_CHARS }