Remove provider-constants-slice.ts in favor of direct constant imports

[bcotrim]

Related issues

• Fixes STU-1378

How AI was used in this PR

AI was used to generate the initial version, some manual adjustments to remove unnecessary type casts.

Proposed Changes

• Delete the Redux slice provider-constants-slice.ts which stored static PHP and WordPress version constants as Redux state
• Replace all Redux selectors with direct constant imports from @studio/common/constants and @studio/common/types/php-versions
• Updated 6 files to use constants directly instead of Redux state
• Removed unnecessary local variable redeclarations and type casts
• Removed test setup code that was dispatching Redux actions for static constants

Testing Instructions

• TypeScript type checker passes
• All 5 tests in use-add-site.test.tsx pass
• Linter passes with no warnings

Pre-merge Checklist

• TypeScript errors checked

[wpmobilebot]

📊 Performance Test Results

Comparing d9878ee vs trunk

app-size

Metric	trunk	d9878ee	Diff	Change
App Size (Mac)	1278.62 MB	1278.61 MB	0.01 MB	⚪ 0.0%

site-editor

Metric	trunk	d9878ee	Diff	Change
load	1889 ms	1919 ms	+30 ms	⚪ 0.0%

site-startup

Metric	trunk	d9878ee	Diff	Change
siteCreation	6086 ms	6124 ms	+38 ms	⚪ 0.0%
siteStartup	3942 ms	3941 ms	1 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[fredrikekelund]

Looking good overall, but I left one comment that would be good to address before landing

[fredrikekelund]

AFAICT, these two props are only consumed in apps/studio/src/modules/add-site/index.tsx. Could we remove them from this file and just import DEFAULT_PHP_VERSION and DEFAULT_WORDPRESS_VERSION directly in that file?

[bcotrim]

Nice catch!

[katinthehatsite]

I think the changes look good. I did not see any regressions and I think that this is a reasonable optimization 👍