Support logging details of calls to json-prune-fetch-response

Example:

    example.com##+js(json-prune-fetch-response)

This will output to the logger details of all fetch() with a
Response.json() call.

Related discussion:
uBlockOrigin/uAssets#22556

assets/resources/scriptlets.js

@@ -1198,10 +1198,10 @@ function jsonPruneFetchResponseFn(
     const extraArgs = safe.getExtraArgs(Array.from(arguments), 2);
     const propNeedles = parsePropertiesToMatch(extraArgs.propsToMatch, 'url');
     const stackNeedle = safe.initPattern(extraArgs.stackToMatch || '', { canNegate: true });
+    const logall = rawPrunePaths === '';
     const applyHandler = function(target, thisArg, args) {
         const fetchPromise = Reflect.apply(target, thisArg, args);
-        if ( rawPrunePaths === '' ) { return fetchPromise; }
-        let outcome = 'match';
+        let outcome = logall ? 'nomatch' : 'match';
         if ( propNeedles.size !== 0 ) {
             const objs = [ args[0] instanceof Object ? args[0] : { url: args[0] } ];
             if ( objs[0] instanceof Request ) {
@@ -1218,14 +1218,18 @@ function jsonPruneFetchResponseFn(
                 outcome = 'nomatch';
             }
         }
-        if ( outcome === 'nomatch' ) { return fetchPromise; }
-        if ( safe.logLevel > 1 ) {
+        if ( logall === false && outcome === 'nomatch' ) { return fetchPromise; }
+        if ( safe.logLevel > 1 && outcome !== 'nomatch' && propNeedles.size !== 0 ) {
             safe.uboLog(logPrefix, `Matched optional "propsToMatch"\n${extraArgs.propsToMatch}`);
         }
         return fetchPromise.then(responseBefore => {
             const response = responseBefore.clone();
             return response.json().then(objBefore => {
                 if ( typeof objBefore !== 'object' ) { return responseBefore; }
+                if ( logall ) {
+                    safe.uboLog(logPrefix, safe.JSON_stringify(objBefore, null, 2));
+                    return responseBefore;
+                }
                 const objAfter = objectPruneFn(
                     objBefore,
                     rawPrunePaths,