fix: make react-select loading and no-options strings translatable

[faisalahammad]

Summary

The async Campaign filter dropdowns on the Donations (Select Campaign) and Donors (All Campaigns) admin list tables rendered react-select's hardcoded English defaults (Loading... and No options) because the shared AsyncFilter wrapper did not pass loadingMessage and noOptionsMessage. Both props are now passed through __() from @wordpress/i18n so they follow the active site language.

Fixes #8165

Changes

src/Views/Components/ListTable/CustomFilter/index.tsx

Before:

<AsyncPaginate
    inputId={`givewp-async-filter-${name}`}
    placeholder={placeholder}
    loadOptions={loadOptions}
    onChange={handleChange}
    value={selectedOption}
    isSearchable={isSearchable}
    isClearable={isClearable}
    mapOptionsForMenu={mapOptionsForMenu}
    className={`${styles.searchableSelect} ${styles.asyncSelect}`}
    classNamePrefix="searchableSelect"
    debounceTimeout={600}
/>

After:

<AsyncPaginate
    inputId={`givewp-async-filter-${name}`}
    placeholder={placeholder}
    loadOptions={loadOptions}
    onChange={handleChange}
    value={selectedOption}
    isSearchable={isSearchable}
    isClearable={isClearable}
    mapOptionsForMenu={mapOptionsForMenu}
    className={`${styles.searchableSelect} ${styles.asyncSelect}`}
    classNamePrefix="searchableSelect"
    debounceTimeout={600}
    loadingMessage={() => __('Loading…', 'give')}
    noOptionsMessage={() => __('No options', 'give')}
/>

Why: The Campaign dropdown on both list tables renders through this single AsyncFilter component (via the campaignselect filter type). Adding the two props here covers both pages with one change and matches the pattern already used in src/Admin/fields/AsyncSelectOption/index.tsx.

Testing

Test 1: Donations list, non-English locale

1. Set site language to a non-en_US locale (e.g. Dutch nl_NL).
2. Go to Donations > Donations.
3. Open the Select Campaign filter dropdown.
4. Observe the loading text while options load, and the empty text when no campaigns match.
   Result: both strings follow the active site language instead of English.

Test 2: Donors list, non-English locale

1. Same locale setup as above.
2. Go to Donations > Donors.
3. Open the All Campaigns filter dropdown.
   Result: loading and empty strings are translated, no hardcoded English.

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