fix: skip port deletion when instances have no port (#779)

diff --git a/images/builder/Earthfile b/images/builder/Earthfile
new file mode 100644
index 0000000..b7025b4
--- /dev/null
+++ b/images/builder/Earthfile
@@ -0,0 +1,7 @@
+VERSION 0.7
+
+image:
+  FROM ../base+image
+  DO ../+APT_INSTALL --packages "build-essential git python3-dev python3-pip python3-venv"
+  ARG POETRY_VERSION=1.4.2
+  RUN pip3 install --no-cache-dir poetry==${POETRY_VERSION}