Rename `EWE.subscriptions.removeAll` to `EWE.subscriptions._removeAll`
Background
EWE.subscriptions.removeAll is a private undocumented function used by the tests to reset filter and subscription state between tests.
What to change
We should rename the function to _removeAll to indicate more clearly that it is only for internal use.
Integration notes
Non-public method EWE.subscriptions.removeAll() is moved to EWE.testing._removeAllSubscriptions().
Edited by Anton Smirnov