Removed unreachable threshold verification code from Levenshtein algorithm implementation classes (#730)

Co-authored-by: TheRealHaui <[email protected]>

Author: TheRealHaui

src/main/java/org/apache/commons/text/similarity/DamerauLevenshteinDistance.java

@@ -54,10 +54,6 @@ private static <E> int limitedCompare(SimilarityInput<E> left, SimilarityInput<E
             throw new IllegalArgumentException("Left/right inputs must not be null");
         }
 
-        if (threshold < 0) {
-            throw new IllegalArgumentException("Threshold can not be negative");
-        }
-
         // Implementation based on https://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance#Optimal_string_alignment_distance
 
         int leftLength = left.length();

src/main/java/org/apache/commons/text/similarity/LevenshteinDetailedDistance.java

@@ -159,9 +159,7 @@ private static <E> LevenshteinResults limitedCompare(SimilarityInput<E> left, Si
         if (left == null || right == null) {
             throw new IllegalArgumentException("CharSequences must not be null");
         }
-        if (threshold < 0) {
-            throw new IllegalArgumentException("Threshold must not be negative");
-        }
+
         /*
          * This implementation only computes the distance if it's less than or equal to the threshold value, returning -1 if it's greater. The advantage is
          * performance: unbounded distance is O(nm), but a bound of k allows us to reduce it to O(km) time by only computing a diagonal stripe of width 2k + 1

src/main/java/org/apache/commons/text/similarity/LevenshteinDistance.java

@@ -81,9 +81,6 @@ private static <E> int limitedCompare(SimilarityInput<E> left, SimilarityInput<E
         if (left == null || right == null) {
             throw new IllegalArgumentException("CharSequences must not be null");
         }
-        if (threshold < 0) {
-            throw new IllegalArgumentException("Threshold must not be negative");
-        }
 
         /*
          * This implementation only computes the distance if it's less than or equal to the threshold value, returning -1 if it's greater. The advantage is