feat: add OpenRPC validator support for extension schemas

[maggie98choy]

What

What does this PR add or remove?

Why

Why are these changes needed?

How

How do these changes achieve the goal?

Test

How has this been tested? How can a reviewer test it?

Checklist

• I have self-reviewed this PR
• I have added tests that prove the feature works or the fix is effective

[github-actions]

Package	Line Rate	Health
core.sdk.src.extn.client	91%	✔
core.main.src.firebolt.handlers	9%	❌
core.tdk.src.utils	0%	❌
core.sdk.src.api	78%	✔
core.main.src.broker	42%	➖
core.main.src.broker.thunder	54%	➖
core.launcher.src.manager	7%	❌
core.main.src.service.apps	47%	➖
core.sdk.src.extn	83%	✔
device.thunder.src.bootstrap	0%	❌
device.thunder_ripple_sdk.src.bootstrap	0%	❌
core.tdk.src.gateway	100%	✔
device.thunder_ripple_sdk.src.client	74%	➖
core.launcher.src	0%	❌
device.thunder_ripple_sdk.src.processors.events	0%	❌
core.main.src.bootstrap.manifest	0%	❌
core.sdk.src.api.gateway	85%	✔
core.sdk.src.utils	53%	➖
core.sdk.src.api.firebolt	77%	✔
device.thunder_ripple_sdk.src.events	4%	❌
core.sdk.src.api.distributor	84%	✔
device.thunder.src	0%	❌
core.main.src.state	25%	❌
core.main.src.service.extn	40%	❌
openrpc_validator.src	90%	✔
core.main.src.bootstrap.extn	0%	❌
core.main.src.firebolt	4%	❌
core.sdk.src.framework	75%	➖
core.main.src.utils	29%	❌
core.main.src	0%	❌
core.main.src.service	31%	❌
core.main.src.processor	0%	❌
core.main.src.processor.storage	0%	❌
core.main.src.state.cap	43%	➖
device.mock_device.src	52%	➖
device.thunder_ripple_sdk.src	15%	❌
core.sdk.src.extn.ffi	80%	✔
core.main.src.bootstrap	0%	❌
core.sdk.src.api.device	77%	✔
device.thunder_ripple_sdk.src.processors	10%	❌
core.sdk.src.api.manifest	91%	✔
core.sdk.src.api.observability	68%	➖
distributor.general.src	2%	❌
Summary	44% (18034 / 41334)	➖

Minimum allowed line rate is 42%