bazel: fix install script default path for standalone builds

Change default DEST_DIR from orfs-specific path to workspace-local path.
The previous default assumed OpenROAD was part of OpenROAD-flow-scripts.

Users can now:
- Install to default: bazel run :install
- Install to custom: bazel run :install -- /custom/path

Fixes #9775

Signed-off-by: alokkumardalei-wq <alokkumardalei2@gmail.com>

Author: alokkumardalei-wq

bazel/install.sh

@@ -2,10 +2,12 @@
 set -e
 
 # Install binary and runfiles from bazel build
+# Usage: bazel run :install -- [DEST_DIR]
+# Default: installs to ./bazel-install in the workspace root
 
 TARFILE=$(cd $BUILD_WORKSPACE_DIRECTORY; bazelisk info bazel-bin)/openroad.tar
 
-DEST_DIR=${1:-${BUILD_WORKSPACE_DIRECTORY}/../install/OpenROAD/bin}
+DEST_DIR=${1:-${BUILD_WORKSPACE_DIRECTORY}/bazel-install}
 
 mkdir -p "$DEST_DIR"
 cp -f "$TARFILE" "$DEST_DIR"