Add missing blueprints library dep

[brandonpayton]

Motivation for the change, related issues

The ajv library was listed as a dev dependency, but it is used by the actual blueprints library.
Without this, consumers of the @wp-playground/blueprints library encounter an error due to missing ajv lib.

npx --yes @wp-playground/cli start                           
node:internal/errors:496
    ErrorCaptureStackTrace(err);
    ^

Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'ajv' imported from /Users/brandon/src/temp/node_modules/@wp-playground/blueprints/index.js
    at new NodeError (node:internal/errors:405:5)
    at packageResolve (node:internal/modules/esm/resolve:916:9)
    at moduleResolve (node:internal/modules/esm/resolve:973:20)
    at defaultResolve (node:internal/modules/esm/resolve:1193:11)
    at ModuleLoader.defaultResolve (node:internal/modules/esm/loader:404:12)
    at ModuleLoader.resolve (node:internal/modules/esm/loader:373:25)
    at ModuleLoader.getModuleJob (node:internal/modules/esm/loader:250:38)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:76:39)
    at link (node:internal/modules/esm/module_job:75:36) {
  code: 'ERR_MODULE_NOT_FOUND'
}

Related to #1630

Implementation details

This PR switches ajv from a dev dependency to a normal dependency.

Testing Instructions (or ideally a Blueprint)

CI