fix(ssr): fix compatibility with webpack@4 and webpack@5 for monorepos

[hardfist]

What kind of change does this PR introduce? (check at least one)

• [x] Bugfix
• [ ] Feature
• [ ] Code style update
• [ ] Refactor
• [ ] Build-related changes
• [ ] Other, please describe:

Does this PR introduce a breaking change? (check one)

• [ ] Yes
• [x] No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• [x] It's submitted to the dev branch for v2.x (or to a previous version branch), not the master branch
• [x] When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• [x] All tests are passing: https://github.com/vuejs/vue/blob/dev/.github/CONTRIBUTING.md#development-setup
• [ ] New/updated tests are included

If adding a new feature, the PR's description includes:

• [ ] A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information: The current webpack version detect logic is flaw in monorepo with webpack@4 and webpack@5, webpack expose its version by compiler.webpack.version since [email protected](https://github.com/webpack/webpack/pull/11657 [email protected] is the only exception), other webpack plugin meets the same problem, see https://github.com/webpack-contrib/mini-css-extract-plugin/pull/636