Fix NPE when there is mismatch in num of kafka partitions

lets say latest checkpoint in deltastreamer has 5 kafka partition offset. Users deleted and re-created and now there is only one kafka partition. So, when checking for new offsets, we run into NPE. 

We might need to fix the parsing logic to accommodate only new partitions. 

stacktrace:
{code:java}
23/07/06 16:07:52 ERROR DeltaStreamer : Failed to run job for table: ABC
java.lang.NullPointerException
at org.apache.hudi.utilities.sources.helpers.KafkaOffsetGen.lambda$fetchValidOffsets$1(KafkaOffsetGen.java:404)
at java.util.stream.MatchOps$1MatchSink.accept(MatchOps.java:90)
at java.util.HashMap$EntrySpliterator.tryAdvance(HashMap.java:1744)
at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126)
at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:499)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:486)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
at java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:230)
at java.util.stream.MatchOps$MatchOp.evaluateSequential(MatchOps.java:196)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.anyMatch(ReferencePipeline.java:516)
at org.apache.hudi.utilities.sources.helpers.KafkaOffsetGen.fetchValidOffsets(KafkaOffsetGen.java:404)
at org.apache.hudi.utilities.sources.helpers.KafkaOffsetGen.getNextOffsetRanges(KafkaOffsetGen.java:317)
at org.apache.hudi.utilities.sources.KafkaSource.fetchNewData(KafkaSource.java:67)
at org.apache.hudi.utilities.sources.Source.fetchNext(Source.java:105)
at org.apache.hudi.utilities.deltastreamer.SourceFormatAdapter.fetchNewDataInRowFormat(SourceFormatAdapter.java:288)
at org.apache.hudi.utilities.deltastreamer.DeltaSync.fetchFromSource(DeltaSync.java:477)
at org.apache.hudi.utilities.deltastreamer.DeltaSync.readFromSource(DeltaSync.java:451)
at org.apache.hudi.utilities.deltastreamer.DeltaSync.syncOnce(DeltaSync.java:358)
at org.apache.hudi.utilities.deltastreamer.HoodieDeltaStreamer$DeltaSyncService.ingestOnce(HoodieDeltaStreamer.java:876)
at org.apache.hudi.common.util.Option.ifPresent(Option.java:97)
at {code}
Code snippet of interest 
{code:java}
private Map fetchValidOffsets(KafkaConsumer consumer,
Option lastCheckpointStr, Set topicPartitions) {
Map earliestOffsets = consumer.beginningOffsets(topicPartitions);
Map checkpointOffsets = CheckpointUtils.strToOffsets(lastCheckpointStr.get());
boolean isCheckpointOutOfBounds = checkpointOffsets.entrySet().stream()
.anyMatch(offset -> offset.getValue() < earliestOffsets.get(offset.getKey())); {code}
last time where we do earliestOffsets.get(offset.getKey()) runs into NPE. 

## JIRA info

- Link: https://issues.apache.org/jira/browse/HUDI-6502
- Type: Bug

Start in org.apache.hudi.utilities.sources.helpers.KafkaOffsetGen.fetchValidOffsets at KafkaOffsetGen.java:404, then inspect CheckpointUtils.strToOffsets and the callers shown in the stack trace. Reproduce a checkpoint with five partitions against a topic with one, and verify the completed change handles missing partitions without an NPE.

Written by the indexing model from the issue text.