Speed up blob presenter specs

What does this MR do and why?

This MR improves the runtime of blob presenter spec by not creating unnecessary project factory.

This spec can be run in random order.

Contributes to #407877

Contributes to &8745.

RSpec Profiling

Here's the output from test-prof when run with FPROF=1. Note:

• Total amount of factories created went down from 21 to 1 🚀
• Total events went down from 2035 to 44
• Queries saved: 1991

Before

Finished in 20.91 seconds (files took 6.71 seconds to load)
20 examples, 0 failures

Randomized with seed 27353

[TEST PROF INFO] Time spent in factories: 00:12.830 (59.35% of total time)
[TEST PROF INFO] Factories usage

 Total: 41
 Total top-level: 21
 Total time: 00:12.830 (out of 00:25.743)
 Total uniq factories: 3

   total   top-level     total time      time per call      top-level time               name

      20          20       12.8155s            0.6408s            12.8155s            project
      20           0        3.1037s            0.1552s             0.0000s          namespace
       1           1        0.0146s            0.0146s             0.0146s            license

After

Finished in 8.48 seconds (files took 6.27 seconds to load)
20 examples, 0 failures

Randomized with seed 50348

[TEST PROF INFO] Time spent in factories: 00:00.016 (0.18% of total time)
[TEST PROF INFO] Factories usage

 Total: 1
 Total top-level: 1
 Total time: 00:00.016 (out of 00:12.945)
 Total uniq factories: 1

   total   top-level     total time      time per call      top-level time               name

       1           1        0.0164s            0.0164s             0.0164s            license

How to set up and validate locally

bin/rspec ./spec/presenters/blobs/unfold_presenter_spec.rb

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.