Custom resource build should use the `build` npm script specified in its `package.json`

### Is this feature request related to a new or existing Amplify category?

_No response_

### Is this related to another service?

_No response_

### Describe the feature you'd like to request

instead of invoking `node_modules/.bin/tsc` directly to build custom resources, we should instead use the defined `build` script in the resource's `package.json`. This script is automatically added when we add a custom resource with `amplify add custom`

ref #11851

### Describe the solution you'd like

see above

### Describe alternatives you've considered

n/a

### Additional context

_No response_

### Is this something that you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request

### Would this feature include a breaking change?

- [ ] ⚠️ This feature might incur a breaking change

Start by locating the custom-resource build path that invokes node_modules/.bin/tsc, then inspect how the resource's package.json is created and read. Confirm the implementation uses that package's defined build script instead of invoking tsc directly, and verify custom-resource builds still complete successfully.

Written by the indexing model from the issue text.