Fixed return type hint for Di::getInternalEventsManager

[sergeyklay]

Hello!

• Type: bug fix
• Link to issue: [BUG]: Wrong return type for Phalcon\Di::getInternalEventsManager #14992

In raising this pull request, I confirm the following:

• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I have updated the relevant CHANGELOG
• I have created a PR for the documentation about this change

Small description of change:

• Fixed return type hint for Phalcon\Di::getInternalEventsManager
• Changed default value for Phalcon\Di::getInternalEventsManager:$services to empty array
• Changed default value for Phalcon\Di::getInternalEventsManager:$sharedInstances to empty array
• Adjusted tests

Thanks