fix(typescript_indexer): emit overrides edges for methods that are 2+ levels away

[nbeloglazov]

This fixes the following scenario:

class One { 
  doStuff() {}
}

class Two extends One {}

class Three extends Two {
  override doStuff() {}
}

Previously TS indexer didn't emit overrides edge between doStuff methods. Now TS indexer traverses all parent class chain until it finds a class/interface that contains method in question or until it reaches base class/interface.