chore(deps): update dependency go to v1.25.9 (#4971)

Co-authored-by: renovate-rancher[bot] <119870437+renovate-rancher[bot]@users.noreply.github.com>

Author: renovate-rancher[bot]

go.mod

@@ -2,7 +2,7 @@ module github.com/rancher/fleet
 
 go 1.24.0
 
-toolchain go1.25.8
+toolchain go1.25.9
 
 replace (
 	github.com/imdario/mergo => github.com/imdario/mergo v1.0.2

integrationtests/go.mod

@@ -2,7 +2,7 @@ module github.com/rancher/fleet/integrationtests
 
 go 1.24.0
 
-toolchain go1.25.8
+toolchain go1.25.9
 
 replace (
 	github.com/rancher/fleet => ../

pkg/apis/go.mod

@@ -2,7 +2,7 @@ module github.com/rancher/fleet/pkg/apis
 
 go 1.24.0
 
-toolchain go1.25.8
+toolchain go1.25.9
 
 require (
 	github.com/rancher/wrangler/v3 v3.3.1