(crawler) Do not remove W/-prefix on weak e-tags

The server expects to get them back prefixed, as we received them.

code/processes/crawling-process/java/nu/marginalia/crawl/fetcher/ContentTags.java

@@ -20,34 +20,11 @@ public record ContentTags(String etag, String lastMod) {
     public void paint(Request.Builder getBuilder) {
 
         if (etag != null) {
-            getBuilder.addHeader("If-None-Match", ifNoneMatch());
+            getBuilder.addHeader("If-None-Match", etag);
         }
 
         if (lastMod != null) {
-            getBuilder.addHeader("If-Modified-Since", ifModifiedSince());
+            getBuilder.addHeader("If-Modified-Since", lastMod);
         }
     }
-
-    private String ifNoneMatch() {
-        // Remove the W/ prefix if it exists
-
-        //'W/' (case-sensitive) indicates that a weak validator is used. Weak etags are
-        // easy to generate, but are far less useful for comparisons. Strong validators
-        // are ideal for comparisons but can be very difficult to generate efficiently.
-        // Weak ETag values of two representations of the same resources might be semantically
-        // equivalent, but not byte-for-byte identical. This means weak etags prevent caching
-        // when byte range requests are used, but strong etags mean range requests can
-        // still be cached.
-        // - https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag
-
-        if (null != etag && etag.startsWith("W/")) {
-            return etag.substring(2);
-        } else {
-            return etag;
-        }
-    }
-
-    private String ifModifiedSince() {
-        return lastMod;
-    }
 }