[duplicated subtitle] perf(SubtitleDeduplicator): compile TTML <p> pattern once for efficiency

- Replace defineTtmlSubtitlePattern() method with a static final Pattern
- getTtmlMatcher() now reuses the precompiled pattern instead of recompiling each call
- Improves performance when processing multiple subtitles without changing behavior

Author: TransZAllen

app/src/main/java/org/schabi/newpipe/util/subtitle/SubtitleDeduplicator.java

@@ -372,15 +372,13 @@ private static boolean stringIsNullOrEmpty(final String inputString) {
         return false;
     }
 
-    private static Pattern defineTtmlSubtitlePattern() {
-        return Pattern.compile(
-            "<p[^>]*begin=\"([^\"]+)\"[^>]*end=\"([^\"]+)\"[^>]*>(.*?)</p>",
-            Pattern.DOTALL
-        );
-    }
+    private static final Pattern TTML_PARAGRAPH_PATTERN = Pattern.compile(
+        "<p[^>]*begin=\"([^\"]+)\"[^>]*end=\"([^\"]+)\"[^>]*>(.*?)</p>",
+        Pattern.DOTALL
+    );
 
     private static Matcher getTtmlMatcher(final String subtitleContent) {
-        final Pattern pattern = defineTtmlSubtitlePattern();
+        final Pattern pattern = TTML_PARAGRAPH_PATTERN;
         return pattern.matcher(subtitleContent);
     }