ci: update Eclipse R search method

Author: AndriiFilippov

releng/update-site-tests/detect-latest-eclipse-steams.sh

@@ -10,19 +10,19 @@ ESP_IDE_BASE="https://dl.espressif.com/dl/idf-eclipse-plugin/ide"
 echo "Fetching Eclipse release list from $RELEASE_XML"
 XML="$(curl -fsSL "$RELEASE_XML")"
 
-# Latest stable R (e.g. 2025-12)
 ECLIPSE_R_RELEASE="$(
   printf '%s\n' "$XML" \
-    | grep -oE '[0-9]{4}-[0-9]{2}/R' \
+    | tr ' ' '\n' \
+    | grep -E '^[0-9]{4}-[0-9]{2}/R$' \
     | sed 's|/R||' \
     | sort -r \
     | head -n1
 )"
 
-# Latest milestone (e.g. 2026-03/M2) - optional
 ECLIPSE_M_RELEASE="$(
   printf '%s\n' "$XML" \
-    | grep -oE '[0-9]{4}-[0-9]{2}/M[0-9]+' \
+    | tr ' ' '\n' \
+    | grep -E '^[0-9]{4}-[0-9]{2}/M[0-9]+$' \
     | sort -r \
     | head -n1 || true
 )"