dictionary label lookup: simplified syntax using the type templated lookup function

Replaced
    readLabel(dict.lookup("name"))
with
    dict.lookup<label>("name)

src/functionObjects/field/fieldAverage/fieldAverage.C

@@ -265,7 +265,7 @@ void Foam::functionObjects::fieldAverage::readAveragingProperties()
             {
                 dictionary fieldDict(propsDict.subDict(fieldName));
 
-                totalIter_[fieldi] = readLabel(fieldDict.lookup("totalIter"));
+                totalIter_[fieldi] = fieldDict.lookup<label>("totalIter");
                 totalTime_[fieldi] = readScalar(fieldDict.lookup("totalTime"));
 
                 Log << "        " << fieldName

src/functionObjects/field/streamLine/streamLine.C

@@ -346,7 +346,7 @@ bool Foam::functionObjects::streamLine::read(const dictionary& dict)
     if (!dict.found("direction") && dict.found("trackForward"))
     {
         trackDirection_ =
-            dict.lookupType<bool>("trackForward")
+            dict.lookup<bool>("trackForward")
           ? trackDirection::forward
           : trackDirection::backward;
     }