Changed geonameID for London to fix build-breaking test

updated the geonameID for LONDON_UK in /src/test/java/com/berico/clavin/resolver/lucene/LuceneLocationResolverHeuristicsTest.java

Listed ID was 2643743, I changed it to 2643741 because this failed test was breaking the build:

Failed tests:   testHeuristicsEngland(com.berico.clavin.resolver.lucene.LuceneLocationResolverHeuristicsTest): LocationResolver chose the wrong "London" expected:<2643743> but was:<2643741>

I'm assuming the problem was similar to this one, an outdated ID:
https://github.com/Berico-Technologies/CLAVIN/pull/17

In this case there is a discrepancy between the geonames entries for London (which contains several boroughs) and the City of London (which is one of those boroughs).