Refactoring on Base64 Text Encoder / Decoder

[veler]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• New feature or enhancement
• UI change (please include screenshot!)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Internationalization and localization
• Other (please describe):

What is the current behavior?

N/A

What is the new behavior?

Addressed some feedback from the previous PR #902

Other information

Quality check

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