[BUG] optional plugin dependency still leads to warning if dependent plugin is not present

Describe the bug

if a plugin is installed which has an optional dependency on another plugin the following warning is nevertheless printed on startup:

{"type": "server", "timestamp": "2026-04-22T13:53:24,973+0000", "level": "WARN", "component": "o.o.p.PluginsService", "cluster.name": "test-opensearch", "node.name": "test-opensearch-0", "message": "Missing plugin [workload-management], dependency of [opensearch-security]" }
{"type": "server", "timestamp": "2026-04-22T13:53:24,973+0000", "level": "WARN", "component": "o.o.p.PluginsService", "cluster.name": "test-opensearch", "node.name": "test-opensearch-0", "message": "Some features of this plugin may not function without the dependencies being installed.\n" }

Related component

Plugins

To Reproduce

1. use the minimal distribution of OpenSearch
2. install the security plugin
3. install the demo configuration for the security plugin (or provide your own configuration)
4. start the cluster

Expected behavior

since it is only an optional dependency it mustn't lead to a warning: the plugin authors (in this case of security) explicitly flagged it as optional, i.e. they deliberately wrote their code so that it can run without it. there is nothing wrong with this setup.

Additional Details

Plugins security

Screenshots n/a

Host/Environment (please complete the following information):

• OS: linux
• Version OpenSearch 3.6.0

Additional context the security plugin defines their dependency here: https://github.com/opensearch-project/security/blob/48934186b6dcf3705b58a0d217745d298b484821/build.gradle#L398