@storybook/angular WebPackConfigOptions is relying on hardcoded `build` target

Describe the bug

Currently, the @storybook/angular plugin is relying hardcoded on the build target from the Angular Architect. This is a problem as it wants to collect the tsConfig information from the build target.

https://github.com/storybookjs/storybook/blob/next/app/angular/src/server/angular-cli_config.ts#L100

// https://github.com/storybookjs/storybook/blob/next/app/angular/src/server/angular-cli_config.ts#L100
 const { options: projectOptions } = project.architect.build;
  const normalizedAssets = normalizeAssetPatterns(
    projectOptions.assets,
    dirToSearch,
    project.sourceRoot
  );
  const projectRoot = path.resolve(dirToSearch, project.root);
  const tsConfigPath = path.resolve(dirToSearch, projectOptions.tsConfig) as Path;

You can not rely on the project options of the hardcoded build target to get the tsConfig as this will result in not finding a tsConfig if you have a build target that has not a tsConfig field.

As you can have a different builder for the architect build step for example:

      "architect": {
        "build": {
          "builder": "@nrwl/workspace:run-commands",
          "options": {
            "parallel": true,
            "commands": [
              {
                "command": "npx ng run my-app:build-frontend"
              },
              {
                "command": "npx ng run my-app:build-server"
              }
            ]
          },

I want to specify storybook which target it should take in this case myapp:build-frontend to get the tsConfig options out of it. Otherwise, it will result in the following Error:

[error] TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received undefined
    at validateString (internal/validators.js:117:11)
    at Object.resolve (path.js:980:7)
    at Object.getAngularCliWebpackConfigOptions (/.../node_modules/@storybook/angular/dist/server/angular-cli_config.js:99:39)
    at Object.webpackFinal (/.../node_modules/@storybook/angular/dist/server/framework-preset-angular-cli.js:7:56)
    at /.../node_modules/@storybook/core/dist/server/presets.js:261:72

[lukasholzer]

So If you want to implement this approach I could help you with that, as it is my daily job, creating angular builders and setup for https://github.com/Dynatrace/barista 😂

[shilman]

@kroeder @lukasholzer this sounds reasonable to me!