ICU-22994 Remove misuage of Calendar::getType

[FrankYFTang]

Use getDynamicClassID and getStaticClassID for calendar type comparision instead of strcmp.
Hide some Hebrew adjustment by using rencently added Calendar API.

dynamic_cast will not work because dynamic_cast(superclass) will not return nullptr for a subclass. For example, ISO8601Calendar is a subclass of GregorianCalendar
and if we have a cal, which could be either a GregorianCalendar or ISO8601Calendar, we cannot depend on dynamic_cast<GregorianCalendar*>(cal) != nullptr to check getType will return “gregorian”

Checklist

• Required: Issue filed: ICU-22994
• Required: The PR title must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Required: The PR description must include the link to the Jira Issue, for example by completing the URL in the first checklist item
• Required: Each commit message must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable

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