esm: only register text format when enabled

[efekrskl]

#62300 broke userland text loaders (more details 1, 2)

This PR aims to fix this by only conditionally adding text import if the feature flag is enabled (similarly to initializeExtensionFormatMap) and adds a regression test

[nodejs-github-bot]

Review requested:

• @nodejs/loaders

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.28%. Comparing base (f00fb75) to head (c1640e8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #64992   +/-   ##
=======================================
  Coverage   90.27%   90.28%           
=======================================
  Files         762      762           
  Lines      247534   247540    +6     
  Branches    46694    46685    -9     
=======================================
+ Hits       223457   223487   +30     
+ Misses      15529    15492   -37     
- Partials     8548     8561   +13     

Files with missing lines	Coverage Δ
lib/internal/modules/esm/assert.js	100.00% <100.00%> (ø)
lib/internal/process/pre_execution.js	97.84% <100.00%> (+0.12%)	⬆️

... and 34 files with indirect coverage changes

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