chore: Update URL pagination endpoint to return results

Previously, it would always return 0 results, which was confusing. For testing purposes, it shouldn't matter that the results are repeated in this context.

After this change:

```console
$ curl -XGET 'http://localhost:8080/pagination/url?attempts=3'
{"numPages":0,"resultArray":[0,1,2,3,4,5,6,7,8],"next":"http://localhost:8080/pagination/url?attempts=2"}
$ curl -XGET 'http://localhost:8080/pagination/url?attempts=2'
{"numPages":0,"resultArray":[0,1,2,3,4,5],"next":"http://localhost:8080/pagination/url?attempts=1"}
$ curl -XGET 'http://localhost:8080/pagination/url?attempts=1'
{"numPages":0,"resultArray":[0,1,2]}
$ curl -XGET 'http://localhost:8080/pagination/url?attempts=0'
{"numPages":0,"resultArray":[]}
```

Author: bflad

internal/pagination/service.go

@@ -158,6 +158,11 @@ func HandleURL(w http.ResponseWriter, r *http.Request) {
 		ResultArray: make([]interface{}, 0),
 	}
 
+	// Return 9, 6, then 3 results for 18 total results.
+	for i := 0; i < total && len(res.ResultArray) < (attempts*3); i++ {
+		res.ResultArray = append(res.ResultArray, i)
+	}
+
 	if attempts > 1 {
 		baseURL := fmt.Sprintf("%s://%s", r.URL.Scheme, r.Host)
 		if r.URL.Scheme == "" { // Fallback if Scheme is not available