Remove . from CLI's classpath on Unix-like platforms

Previously, the spring bash script added . to the classpath but the
Windows spring.bat script did not. This commit aligns the classpath
of the two scripts by removing . from the classpath in the bash
script.

Fixes gh-19910

spring-boot-project/spring-boot-cli/src/main/executablecontent/bin/spring

@@ -99,7 +99,7 @@ if [ ! -d "${SPRING_HOME}" ]; then
 	exit 2
 fi
 
-CLASSPATH=.:${SPRING_HOME}/bin
+CLASSPATH=${SPRING_HOME}/bin
 if [ -d "${SPRING_HOME}/ext" ]; then
 	CLASSPATH=$CLASSPATH:${SPRING_HOME}/ext
 fi