Similiarize Structured1D to Tree1D

[DanielDoehring]

For 1D TreeMeshes, the user can specify the coordinates as a tuple (1.0) or as a Float: 1.0. This was not possible for 1D StructuredMesh. Loosely related to #1194

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.36%. Comparing base (806c1b9) to head (0c9ebb6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2153   +/-   ##
=======================================
  Coverage   96.36%   96.36%           
=======================================
  Files         480      480           
  Lines       38067    38069    +2     
=======================================
+ Hits        36682    36684    +2     
  Misses       1385     1385           

Flag	Coverage Δ
unittests	96.36% <100.00%> (+<0.01%)	⬆️

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