More improvements to `map` and `similar` on `QuantityArray`

[MilesCranmer]

Fixes:

• map when the result is not a quantity (e.g., map(x -> ustrip(x), qa))
• similar(::QuantityArray, ::Type{<:UnionAbstractQuantity})

[github-actions[bot]]

Benchmark Results

	main	2c64dc4d64b883...	t[main]/t[2c64dc4d64b883...]
Quantity/creation/Quantity(x)	2.8 ± 0.91 ns	3.1 ± 0.01 ns	0.903
Quantity/creation/Quantity(x, length=y)	3.11 ± 0.001 ns	3.11 ± 0.92 ns	1
Quantity/with_numbers/*real	3.1 ± 0.01 ns	3.1 ± 0.01 ns	1
Quantity/with_numbers/^int	8.05 ± 2.2 ns	8.37 ± 2.5 ns	0.963
Quantity/with_numbers/^int * real	8.05 ± 2.2 ns	8.37 ± 2.5 ns	0.963
Quantity/with_quantity/+y	5.27 ± 0.01 ns	5.27 ± 0.01 ns	1
Quantity/with_quantity//y	3.41 ± 0.01 ns	3.11 ± 0.01 ns	1.1
Quantity/with_self/dimension	1.55 ± 0.01 ns	1.55 ± 0.01 ns	1
Quantity/with_self/inv	3.11 ± 0.01 ns	3.11 ± 0.01 ns	1
Quantity/with_self/ustrip	1.56 ± 0.01 ns	1.55 ± 0.01 ns	1.01
QuantityArray/broadcasting/multi_array_of_quantities	0.147 ± 0.14 ms	0.146 ± 0.14 ms	1.01
QuantityArray/broadcasting/multi_normal_array	0.0531 ± 0.0003 ms	0.05 ± 0.0013 ms	1.06
QuantityArray/broadcasting/multi_quantity_array	0.159 ± 0.0007 ms	0.159 ± 0.00095 ms	1
QuantityArray/broadcasting/x^2_array_of_quantities	26.6 ± 2.2 μs	27.7 ± 2.9 μs	0.958
QuantityArray/broadcasting/x^2_normal_array	5.99 ± 0.5 μs	4.78 ± 0.68 μs	1.25
QuantityArray/broadcasting/x^2_quantity_array	6.19 ± 0.38 μs	7.04 ± 0.34 μs	0.879
QuantityArray/broadcasting/x^4_array_of_quantities	0.0787 ± 0.00068 ms	0.0788 ± 0.00067 ms	0.998
QuantityArray/broadcasting/x^4_normal_array	0.0498 ± 0.00019 ms	0.0499 ± 0.00025 ms	0.999
QuantityArray/broadcasting/x^4_quantity_array	0.0654 ± 0.006 ms	0.0592 ± 0.00021 ms	1.1
time_to_load	0.241 ± 0.0039 s	0.246 ± 0.0069 s	0.98

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR. Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).