fix(vue-renderer): fix meta injection when ssr renderer generates a spa page

[pimlie]

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Resolves: nuxt/vue-meta#567

Description

On nuxt generate in universal mode normally all pages are serverRendered: true, but redirects will be generated as a spa. This PR makes sure that vue-meta is aware of that as well and doesnt add its own ssr attributes.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly. (PR: #)
• I have added tests to cover my changes (if not applicable, please state why)
• All new and existing tests are passing.

[codecov-commenter]

Codecov Report

Merging #7439 into dev will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##              dev    #7439      +/-   ##
==========================================
- Coverage   70.20%   70.16%   -0.04%     
==========================================
  Files          88       88              
  Lines        3715     3717       +2     
  Branches     1008     1008              
==========================================
  Hits         2608     2608              
- Misses        899      901       +2     
  Partials      208      208              

Flag	Coverage Δ
#unittests	70.16% <0.00%> (-0.04%)	⬇️

Impacted Files	Coverage Δ
packages/vue-renderer/src/renderers/ssr.js	0.00% <0.00%> (ø)

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[pimlie]

@pi0 It seems that the tests are logging the following message, is that a known issue? Ie its not just just for me locally but also in the 2.13 draft pr

ReferenceError: You are trying to `import` a file after the Jest environment has been torn down.

[pimlie]

This PR also adds the change that during development all generated tags by vue-meta will be appended by a line break.