[BBND-291] Remove environment variables that are unnecessarily required

[pathornteng]

The public key can be derived from the private key. We do not have to require the user to enter the public key in .env file.

The following environment variables in .env can be removed

TESTNET_HEDERA_OPERATOR_PUBLICKEY
TESTNET_HEDERA_NON_OPERATOR_PUBLICKEY
PREVIEWNET_HEDERA_OPERATOR_PUBLICKEY
PREVIEWNET_HEDERA_NON_OPERATOR_PUBLICKEY

To derive the public key from the private key just use the code below

privateKey.publicKey

In addition, the key type should not be required as the SDK should be able to distinguish the private key by itself. The following environment variables should also be removed

TESTNET_HEDERA_OPERATOR_ED25519
TESTNET_HEDERA_NON_OPERATOR_ED25519
PREVIEWNET_HEDERA_OPERATOR_ED25519
PREVIEWNET_HEDERA_NON_OPERATOR_ED25519

[MiguelLZPF]

Hey @pathornteng! Sorry for the late response 🙏🏽, we lost this issue in the backlog.
As the ENV variables are only used for testing, it is not urgent to address the issue. Anyway, we have marked it as "improvement" and will look into it when we have spare time in following sprints.

[MiguelLZPF]

BBND-291