feat(core): warn when broadcast with channels but not found

[codecov[bot]]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (a82c25f) 88.52% compared to head (f3ff45e) 88.45%.

Files	Patch %	Lines
packages/core/src/database.ts	44.44%	5 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1349 +/- ## ========================================== - Coverage 88.52% 88.45% -0.08% ========================================== Files 37 37 Lines 5379 5386 +7 Branches 1072 1072 ========================================== + Hits 4762 4764 +2 - Misses 617 622 +5 ```

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