Modified formatter for default address

[jimni1222]

Proposed changes

This PR introduces modification for default address in formatter.

When a contract deploy transaction wants to sign an RLP-encoded raw string, decode the string and return '0x' in the to field.
In such cases, the current logic throws an error with an invalid address.

An if statement has been added to handle this.

Types of changes

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• Bugfix
• New feature or enhancement
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Related issues

refer #117

Further comments

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