add StrictValidation to BundleCompositionConfig to support more user friendly errors on invalid specs

[tx3stn]

Add a StrictValidation field to BundleCompositionConfig to handle reporting errors when trying to compose the bundle.

Scenario

I've run into an issue using the bundler, where an invalid spec was causing a confusing error which states a file did not exist, if a component was trying to refer to another component whilst including an invalid sibling ref node, i.e.:

spec:

openapi: 3.0.0
info:
  title: Historical Shipping Option Repro
  version: 1.0.0
paths:
  /shipments:
    post:
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: ./components/HistoricalShippingOption.json
      responses:
        '200':
          description: ok

./components/CountryCode.json

{
  "type": "string",
  "description": "Country code in ISO 3166 ALPHA-2 format",
  "enum": [
    "US",
    "CA",
    "GB",
    "DE",
    "FR"
  ]
}

./components/HistoricalShippingOption.json

{
  "title": "HistoricalShippingOption",
  "type": "object",
  "properties": {
    "country_code": {
      "$ref": "CountryCode.json",
      "description": "this should not be here"
    }
  },
  "required": [
    "country_code"
  ]
}

Warning

This is invalid, the country_code property should not have a description with the $ref.

Deleting this description key fixes everything, but teams using this have been confused by how this error is reported.

The bundle gets created incorrectly, and linting then says rolodex count not find file for the external ref CountryCode.json, which is confusing as it's not that the file can't be found, it's the input is invalid.

Example code for bundling:

	docConfig := &datamodel.DocumentConfiguration{
		AllowFileReferences:       true,
		AllowRemoteReferences:     true,
		BasePath:                  c.basePath,
		BundleInlineRefs:          false,
		ExtractRefsSequentially:   true,
		Logger:                    slogLogger,
		MergeReferencedProperties: false,
		RecomposeRefs:             true,
		SpecFilePath:              c.inputFile,
	}

	compositionConfig := &bundler.BundleCompositionConfig{
		Delimiter: "__",
	}

	bundled, err := bundler.BundleBytesComposed(
		specBytes,
		docConfig,
		compositionConfig,
	)

When I build with these changes and enable the StrictValidation my specific error gets flagged, which avoids the confusion of the file not found errors that are currently flagged.