Closes #18652: Run housekeeping GitHub actions only on the main repository

.github/workflows/close-incomplete-issues.yml

@@ -12,6 +12,7 @@ permissions:
 
 jobs:
   stale:
+    if: github.repository == 'netbox-community/netbox'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/stale@v9

.github/workflows/close-stale-issues.yml

@@ -13,6 +13,7 @@ permissions:
 
 jobs:
   stale:
+    if: github.repository == 'netbox-community/netbox'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/stale@v9

.github/workflows/lock-threads.yml

@@ -13,6 +13,7 @@ permissions:
 
 jobs:
   lock:
+    if: github.repository == 'netbox-community/netbox'
     runs-on: ubuntu-latest
     steps:
       - uses: dessant/lock-threads@v5

.github/workflows/update-translation-strings.yml

@@ -13,6 +13,7 @@ env:
 
 jobs:
   makemessages:
+    if: github.repository == 'netbox-community/netbox'
     runs-on: ubuntu-latest
     env:
       NETBOX_CONFIGURATION: netbox.configuration_testing