Sentry tests - getSentryHandler method to reduce duplicated code

[rsvoboda]

Sentry tests - getSentryHandler method to reduce duplicated code

[gsmet]

@ia3andy can you have a look?

[ia3andy]

Looks good, @rsvoboda did you also refactor the other Logger tests which use nearly the same code as well?

[rsvoboda]

@ia3andy will double check other logger tests, looked just in sentry ones.

[ia3andy]

@rsvoboda have a look in core/test-extension/deployment/src/test.. and in extensions/logging-json/deployement/src/test/...