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/asr/src/UseCaseHandler.cc b/source/use_case/asr/src/UseCaseHandler.cc
index d469255..f13de0d 100644
--- a/source/use_case/asr/src/UseCaseHandler.cc
+++ b/source/use_case/asr/src/UseCaseHandler.cc
@@ -101,6 +101,8 @@
 
         /* Loop to process audio clips. */
         do {
+            platform.data_psn->clear(COLOR_BLACK);
+
             /* Get current audio clip index. */
             auto currentIndex = ctx.Get<uint32_t>("clipIndex");