Improved Field Classification edit distance algorithms.

The initial implementation was very simple, as the focus was the overall
workflow. Now it uses a proper implementation, copied from
com.android.tools.lint.detector.api.LintUtils.java

Test: atest ExtServicesUnitTests FieldsClassificationTest
Bug: 70291841

Change-Id: I7424b7f03a3c9cf9619c154656fa211b9f0c494a