Fix infinite loop in outer alignment edge case

[smcguire-cmu]

Fixes case where adding new pixels gets pixel size zero when adding new pixels from pixel number 0. This happened when there was an order mismatch with one catalog missing pixel 0 and another catalog having a pixel at 0. Fixes astronomy-commons/lsdb#319

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 94.19%. Comparing base (943e426) to head (827be29).

Files	Patch %	Lines
src/hipscat/pixel_tree/pixel_alignment.py	0.00%	5 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #270 +/- ## ========================================== - Coverage 94.29% 94.19% -0.10% ========================================== Files 56 56 Lines 1963 1965 +2 ========================================== Hits 1851 1851 - Misses 112 114 +2 ```

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Before [943e4263]	After [700f2eb9]	Ratio	Benchmark (Parameter)
19.3±0.6ms	19.8±0.5ms	1.02	benchmarks.MetadataSuite.time_load_partition_info_order6
13.5±0.1ms	13.9±0.08ms	1.02	benchmarks.time_test_cone_filter_multiple_order
13.1±0.3ms	13.2±0.4ms	1.01	benchmarks.Suite.time_inner_pixel_alignment
361±4ms	364±2ms	1.01	benchmarks.Suite.time_outer_pixel_alignment
82.2±2ms	83.4±2ms	1.01	benchmarks.Suite.time_paths_creation
78.1±0.3ms	78.4±0.3ms	1	benchmarks.MetadataSuite.time_load_partition_info_order7
77.1±0.7ms	76.9±0.6ms	1	benchmarks.MetadataSuite.time_load_partition_join_info
123±0.2ms	124±0.3ms	1	benchmarks.time_test_alignment_even_sky
42.3±0.7ms	41.8±1ms	0.99	benchmarks.Suite.time_pixel_tree_creation

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