Allow S3EncryptionClient::putObject to accept any type that implement StreamInterface

[whizsid]

putObject is throwing an exception if user passed a stream implemented to StreamInterface. I checked the usage of $plaintext and found that $plaintext is using only for constructors of AesGcmEncryptingStream and AesEncryptingStream. Those constructors requiring StreamInterface as first arguments. So we do not have to stick into Stream in EncryptionTraits.

Now we are doing like this.

$tfh = tmpfile();
fwrite($tfh, (string)$stream);

$result = $encryptedS3Client->putObject([
      '@MaterialsProvider' => $this->kmsProvider,
      '@CipherOptions' => $cipherOptions,
      'Bucket' => $bucket,
      'Key' => $path,
      'Body' => $tfh,
]);

With this PR we can save some cost like this:-

$result = $encryptedS3Client->putObject([
      '@MaterialsProvider' => $this->kmsProvider,
      '@CipherOptions' => $cipherOptions,
      'Bucket' => $bucket,
      'Key' => $path,
      'Body' => $stream,
]);

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