fix: panic during migration (#21031)

> Related issue: #21030

# Checklist for submitter

If some of the following don't apply, delete the relevant line.

<!-- Note that API documentation changes are now addressed by the
product design team. -->

- [x] Input data is properly validated, `SELECT *` is avoided, SQL
injection is prevented (using placeholders for values in statements)
- [x] Added/updated tests
- [x] Manual QA for all new/changed functionality

---------

Co-authored-by: Sarah Gillespie <73313222+gillespi314@users.noreply.github.com>

server/datastore/mysql/migrations/tables/20240802113716_UpdateSoftwareGitopsConfig.go

@@ -33,8 +33,16 @@ func Up_20240802113716(tx *sql.Tx) error {
 		if err := json.Unmarshal(r.Config, &config); err != nil {
 			return fmt.Errorf("unmarshal team config: %w", err)
 		}
-		softwareData := config["software"]
+		softwareData, ok := config["software"]
+		if !ok {
+			continue
+		}
+
 		rt := reflect.TypeOf(config["software"])
+		if rt == nil {
+			continue
+		}
+
 		if rt.Kind() == reflect.Slice {
 			// then we have an older config without the new fields
 			// Note: we are setting the new key to be whatever the old key was (if it was null, then

server/datastore/mysql/migrations/tables/20240802113716_UpdateSoftwareGitopsConfig_test.go

@@ -159,10 +159,78 @@ func TestUp_20240802113716(t *testing.T) {
     "host_expiry_enabled": true
   }
 }
+`
 
+	badCfgNoSoftwareField := `
+{
+  "mdm": {
+    "ios_updates": {
+      "deadline": "",
+      "minimum_version": ""
+    },
+    "macos_setup": {
+      "bootstrap_package": "",
+      "macos_setup_assistant": "",
+      "enable_end_user_authentication": false,
+      "enable_release_device_manually": false
+    },
+    "macos_updates": {
+      "deadline": "",
+      "minimum_version": ""
+    },
+    "ipados_updates": {
+      "deadline": "",
+      "minimum_version": ""
+    },
+    "macos_settings": {
+      "custom_settings": []
+    },
+    "windows_updates": {
+      "deadline_days": null,
+      "grace_period_days": null
+    },
+    "windows_settings": {
+      "custom_settings": []
+    },
+    "enable_disk_encryption": false
+  },
+  "scripts": [],
+  "features": {
+    "enable_host_users": true,
+    "enable_software_inventory": true
+  },
+  "integrations": {
+    "jira": null,
+    "zendesk": null,
+    "google_calendar": {
+      "webhook_url": "",
+      "enable_calendar_events": false
+    }
+  },
+  "webhook_settings": {
+    "host_status_webhook": {
+      "days_count": 0,
+      "destination_url": "",
+      "host_percentage": 0,
+      "enable_host_status_webhook": false
+    },
+    "failing_policies_webhook": {
+      "policy_ids": null,
+      "destination_url": "",
+      "host_batch_size": 0,
+      "enable_failing_policies_webhook": false
+    }
+  },
+  "host_expiry_settings": {
+    "host_expiry_window": 30,
+    "host_expiry_enabled": true
+  }
+}
 `
+
 	tid1 := execNoErrLastID(t, db, `INSERT INTO teams (name, config) VALUES (?,?)`, "team 1", badCfg)
 	tid2 := execNoErrLastID(t, db, `INSERT INTO teams (name, config) VALUES (?,?)`, "team 2", badCfgEmptyArr)
+	tid3 := execNoErrLastID(t, db, `INSERT INTO teams (name, config) VALUES (?,?)`, "team 3", badCfgNoSoftwareField)
 
 	// Apply current migration.
 	applyNext(t, db)
@@ -180,6 +248,7 @@ func TestUp_20240802113716(t *testing.T) {
 	require.False(t, team.Config.Software.AppStoreApps.Valid)
 	require.Len(t, team.Config.Software.AppStoreApps.Value, 0)
 
+	team = fleet.Team{}
 	require.NoError(t, db.Get(&team, "SELECT id, config FROM teams WHERE id = ?", tid2))
 
 	// Team with an empty array originally should have JSON null set for packages
@@ -191,4 +260,9 @@ func TestUp_20240802113716(t *testing.T) {
 	require.False(t, team.Config.Software.AppStoreApps.Set)
 	require.False(t, team.Config.Software.AppStoreApps.Valid)
 	require.Len(t, team.Config.Software.AppStoreApps.Value, 0)
+
+	team = fleet.Team{}
+	require.NoError(t, db.Get(&team, "SELECT id, config FROM teams WHERE id = ?", tid3))
+
+	require.Nil(t, team.Config.Software)
 }