fix: Allow binary reading value to be empty

[weichou1229]

Since we accept the nil reading value, the binary reading value can be empty

fixes edgex-go#4986

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Testing Instructions

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 44.37%. Comparing base (bbedcee) to head (d524d8c).

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #941 +/- ## ======================================= Coverage 44.37% 44.37% ======================================= Files 124 124 Lines 6895 6895 ======================================= Hits 3060 3060 Misses 3578 3578 Partials 257 257 ```

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