Replace hyphen with underscore in metric name

[badrogger]

Changes

• Replace hyphen with underscore in metric name.

Testing

• Added unit tests.
• Tested on internal network.

Performance

• No performance related changes were introduced.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 68.29268% with 13 lines in your changes missing coverage. Please review.

Project coverage is 81.78%. Comparing base (3f60fac) to head (79ff954).

Files	Patch %	Lines
core/schains/dkg/client.py	76.00%	6 Missing :warning:
core/schains/monitor/main.py	37.50%	5 Missing :warning:
core/schains/checks.py	50.00%	1 Missing :warning:
core/schains/monitor/action.py	75.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1089 +/- ## =========================================== + Coverage 81.63% 81.78% +0.14% =========================================== Files 103 102 -1 Lines 6056 6050 -6 =========================================== + Hits 4944 4948 +4 + Misses 1112 1102 -10 ```

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