[netbox] Add missing default for disable_keep_alive var

The disable_keep_alive variable in the httpjson input was declared as
required: true and show_user: false but with no default value. Because
the variable is hidden from the user and the system tests do not supply
it explicitly, Fleet rejects the package policy with:

  inputs.httpjson.vars.disable_keep_alive: ["Disable HTTP Keep-Alives is required"]

Add default: false (the canonical pattern used by okta and 1password)
so Fleet can satisfy the required constraint without user input.

Closes #18665, #18666, #18667, #18668, #18727, #18728

Author: andrewkroh

packages/netbox/changelog.yml

@@ -1,4 +1,9 @@
 # newer versions go on top
+- version: "0.1.1"
+  changes:
+    - description: Set the default value of the "Disable HTTP Keep-Alives" variable to false to fix package policy validation.
+      type: bugfix
+      link: https://github.com/elastic/integrations/pull/19889
 - version: "0.1.0"
   changes:
     - description: Initial draft of the package

packages/netbox/manifest.yml

@@ -1,7 +1,7 @@
 format_version: 3.4.1
 name: netbox
 title: "NetBox"
-version: 0.1.0
+version: 0.1.1
 source:
   license: "Elastic-2.0"
 description: "Collect logs from NetBox with Elastic Agent"
@@ -88,6 +88,7 @@ policy_templates:
             description: Controls whether HTTP keep-alives are disabled.
             type: bool
             multi: false
+            default: false
 owner:
   github: elastic/obs-infraobs-integrations
   type: elastic