Consolidate ByteArray::from_iterator

[tustvold]

Which issue does this PR close?

Closes #.

Rationale for this change

Reduces code duplication, and is marginally faster for smaller arrays (likely because of StringBuilder has a minimum allocation of 1024 bytes).

array_string_from_vec 128
                        time:   [945.97 ns 946.65 ns 947.40 ns]
                        change: [-19.195% -19.061% -18.890%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 14 outliers among 100 measurements (14.00%)
  4 (4.00%) low mild
  6 (6.00%) high mild
  4 (4.00%) high severe

array_string_from_vec 256
                        time:   [1.6194 µs 1.6204 µs 1.6215 µs]
                        change: [-4.5788% -4.4338% -4.2716%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 5 outliers among 100 measurements (5.00%)
  2 (2.00%) low mild
  1 (1.00%) high mild
  2 (2.00%) high severe

array_string_from_vec 512
                        time:   [2.7773 µs 2.7785 µs 2.7799 µs]
                        change: [-0.1694% -0.0183% +0.1938%] (p = 0.87 > 0.05)
                        No change in performance detected.
Found 9 outliers among 100 measurements (9.00%)
  7 (7.00%) high mild
  2 (2.00%) high severe

What changes are included in this PR?

Are there any user-facing changes?

[wjones127]

Nice simplification!