Allow proxy paths in Heimdall URL (#8940)

Add paths to the hiemdall config URL when creating calls so that extra
paths needs by, for example proxy servers are not stripped from the flag
value passed into the process.

consensus/bor/heimdall/client.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"path"
 	"sort"
 	"strings"
 	"time"
@@ -422,7 +423,7 @@ func makeURL(urlString, rawPath, rawQuery string) (*url.URL, error) {
 		return nil, err
 	}
 
-	u.Path = rawPath
+	u.Path = path.Join(u.Path, rawPath)
 	u.RawQuery = rawQuery
 
 	return u, err