MLECO-2684: Standardize LCD behaviour

* LCD display behavior for Run All now matches Run Next
* Remove repeated code

Signed-off-by: Richard Burton <richard.burton@arm.com>
Change-Id: I16706187fd4e7a59dd935783f5bfb8731435f381
diff --git a/source/use_case/vww/src/UseCaseHandler.cc b/source/use_case/vww/src/UseCaseHandler.cc
index d384032..8165bb0 100644
--- a/source/use_case/vww/src/UseCaseHandler.cc
+++ b/source/use_case/vww/src/UseCaseHandler.cc
@@ -50,8 +50,6 @@
         constexpr uint32_t dataPsnTxtInfStartX = 150;
         constexpr uint32_t dataPsnTxtInfStartY = 70;
 
-
-        platform.data_psn->clear(COLOR_BLACK);
         time_t infTimeMs = 0;
 
         auto& model = ctx.Get<Model&>("model");
@@ -87,6 +85,7 @@
         std::vector<ClassificationResult> results;
 
         do {
+            platform.data_psn->clear(COLOR_BLACK);
 
             /* Strings for presentation/logging. */
             std::string str_inf{"Running inference... "};