Import resolver breaks on complex dynamic import inside of web_modules

[FredKSchott]

Original Discussion: https://www.pika.dev/npm/snowpack/discuss/398
/cc @zalelion

  [error] [404] /web_modules/common/%22%20+%20bundleId%20+%20%22.entry.js%22%20+%20'.js
    ✘ /Users/liangzeng/Documents/web/node_modules/.cache/snowpack/dev/common/" + bundleId + ".entry.js" + '.js
    ✘ /Users/liangzeng/Documents/web/node_modules/.cache/snowpack/dev/common/" + bundleId + ".entry.jsx" + '.js
    ✘ /Users/liangzeng/Documents/web/node_modules/.cache/snowpack/dev/common/" + bundleId + ".entry.ts" + '.js
    ✘ /Users/liangzeng/Documents/web/node_modules/.cache/snowpack/dev/common/" + bundleId + ".entry.tsx" + '.js
    ✘ /Users/liangzeng/Documents/web/node_modules/.cache/snowpack/dev/common/" + bundleId + ".entry.js" + '.jsx

We are supposed to be ignoring complex dynamic imports like this (import('foo'+bar+'baz.js')) but it appears our REGEX for matching against complex imports is broken.

[FredKSchott]

See also: #535