feat: support dedicated host ec2 overrides (#5191)

## Description

Adds support for applying supported dynamic EC2 override labels to
dedicated-host runner launches that use `RunInstances`.

This maps the parsed `ec2OverrideConfig` into the `RunInstances` request
for supported fields:

- `InstanceType`
- `SubnetId`
- `ImageId`
- `Placement`
- `BlockDeviceMappings`

Fleet-only override fields such as `InstanceRequirements`, `MaxPrice`,
`Priority`, and `WeightedCapacity` are intentionally not forwarded to
`RunInstances`.

Also updates the dynamic label documentation to show which EC2 override
labels work with EC2 Fleet and which work with dedicated-host launches.

## Test Plan

- Added unit test coverage for dedicated-host `RunInstances` overrides.
- Verified supported EC2 override config values are passed to
`RunInstances`.
- Verified Fleet-only fields are not passed to `RunInstances`.
- Ran `yarn exec vitest run
functions/control-plane/src/aws/runners.test.ts --config
functions/control-plane/vitest.config.ts`
- Ran `yarn exec eslint functions/control-plane/src/aws/runners.ts
functions/control-plane/src/aws/runners.test.ts`
- Ran `yarn workspace @aws-github-runner/control-plane build`
- Ran `git diff --check`

## Related Issues

N/A

Author: edersonbrilhante