Chart: set workers.safeToEvict default to False (apache#40229)

This is a safer default for our workers.

This can be safe to set to true if you have a long enough
`workers.terminationGracePeriodSeconds` set, but what is
"long enough" is very situational, so I feel its better to
default to not evicting worker pods.

chart/newsfragments/40229.significant.rst

@@ -0,0 +1,6 @@
+``workers.safeToEvict`` default changed to False
+
+The default for ``workers.safeToEvict`` now defaults to False. This is a safer default
+as it prevents the nodes workers are running on from being scaled down by the
+[K8s Cluster Autoscaler](https://kubernetes.io/docs/concepts/cluster-administration/cluster-autoscaling/#cluster-autoscaler).
+If you would like to retain the previous behavior, you can set this config to True.

chart/values.schema.json

@@ -1864,7 +1864,7 @@
                 "safeToEvict": {
                     "description": "This setting tells Kubernetes that it's ok to evict when it wants to scale a node down.",
                     "type": "boolean",
-                    "default": true
+                    "default": false
                 },
                 "extraContainers": {
                     "description": "Launch additional containers into workers (templated). Note, if used with KubernetesExecutor, you are responsible for signaling sidecars to exit when the main container finishes so Airflow can continue the worker shutdown process!",

chart/values.yaml

@@ -676,7 +676,7 @@ workers:
 
   # This setting tells kubernetes that its ok to evict
   # when it wants to scale a node down.
-  safeToEvict: true
+  safeToEvict: false
 
   # Launch additional containers into worker (templated).
   # Note: If used with KubernetesExecutor, you are responsible for signaling sidecars to exit when the main

helm_tests/airflow_core/test_worker.py

@@ -755,7 +755,7 @@ def test_should_add_component_specific_annotations(self):
     @pytest.mark.parametrize(
         "globalScope, localScope, precedence",
         [
-            ({}, {}, "true"),
+            ({}, {}, "false"),
             ({}, {"safeToEvict": True}, "true"),
             ({}, {"safeToEvict": False}, "false"),
             (