feat: validate default_locale INI value upon setting it #115

Job	Run time
Test for Memory Leaks	5m 39s
Coding standards	35s
Code coverage (8.2, 70.1)	1m 40s
Tests: PHP 8.2, ICU 70.1	2m 20s
Tests: PHP 8.2, ICU 71.1	1m 42s
Tests: PHP 8.2, ICU 72.1	1m 32s
Tests: PHP 8.2, ICU 73.1	2m 2s
Tests: PHP 8.2, ICU 73.2	1m 59s
Tests: PHP 8.3, ICU 70.1	2m 41s
Tests: PHP 8.3, ICU 71.1	1m 32s
Tests: PHP 8.3, ICU 72.1	1m 51s
Tests: PHP 8.3, ICU 73.1	2m 3s
Tests: PHP 8.3, ICU 73.2	1m 34s
Install with pecl on php:8.2-cli-alpine3.18	33s
Install with pecl on php:8.2-cli-bookworm	33s
	28m 16s

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