check that node.roles is defined

[mindejulian]

Description

When using the Mock from "@elastic/elasticsearch-mock" the roles on the node are not defined, this pr checks that roles are defined before checking if the node is a cluster_manager or master only node.

Issues Resolved

Closes #640

Check List

• New functionality includes testing.
  • All tests pass
• Linter check was successfull - yarn run lint doesn't show any errors
• Commits are signed per the DCO using --signoff
• Changelog was updated.

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[dblock]

Please add a test and CHANGELOG entry. Thanks!

[mindejulian]

Tried to add tests, but found a nice workaround instead.
const mockClient = new Client({ node: 'http://localhost:9200', nodeFilter: () => { return true }, Connection: mock.getConnection() as unknown as typeof Connection, })

[dblock]

This is still a bug, care to finish a fix? I'll reopen.