Sentry API token needs event:read access

In sentry metrics: add metrics for sentry issues (cki-tools!1628 - merged) a function was added that uses the GET /api/0/organizations/{organization_id_or_slug}/issues/ endpoint. Per that doc, it requires one of the following token scopes:

<auth_token> requires one of the following scopes:
event:admin
event:read
event:write

It turns out the token we use only has project:read scope so when a fresh applecrumble-service-metrics-exporter pod was deployed it got permission denied.

Please give the deployment a token with both project:read and event:read permissions.

Part of: KMAINT-1705