PMM-14829 Bump Go to 1.25.8

[ademidoff]

https://jira.percona.com/browse/PMM-14829

• PMM-14829 Bump Go to 1.25.8 percona/pmm#5117

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4258-67d2585
Client docker: perconalab/pmm-client-fb:PR-4258-67d2585
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4258-67d2585
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4258-67d2585.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4258-67d2585&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4258-67d2585.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/5446/

[JNKPercona]

Server docker: perconalab/pmm-server-fb:PR-4258-e51210f
Client docker: perconalab/pmm-client-fb:PR-4258-e51210f
Watchtower docker: perconalab/pmm-watchtower-fb:PR-4258-e51210f
Client tarball: https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4258-e51210f.tar.gz
Staging instance: https://pmm.cd.percona.com/job/pmm3-aws-staging-start/parambuild/?DOCKER_VERSION=perconalab/pmm-server-fb:PR-4258-e51210f&CLIENT_VERSION=https://s3.us-east-2.amazonaws.com/pmm-build-cache/PR-BUILDS/pmm-client/pmm-client-PR-4258-e51210f.tar.gz

[JNKPercona]

API tests have succeded: https://pmm.cd.percona.com/job/pmm3-api-tests/5469/