Prevent navigation keys from triggering actions during IME composition

[Theproudcold]

Fixes #36532

Refined the Enter key trigger logic in the repository filter to prevent actions during IME composition.

By checking the e.isComposing property, the filter now correctly distinguishes between "confirming an IME candidate" and "submitting the search." This prevents premature search triggers when users press Enter to select Chinese/Japanese characters.

[silverwind]

Looks ok, thanks.

Not required but would be nice maybe to fix it for all places where we bind the Enter key. A quick search reveals:

web_src/js/components/DashboardRepoList.vue-        case 'Enter':
web_src/js/components/RepoBranchTagSelector.vue:      } else if (e.key === 'Enter') {
web_src/js/components/RepoFileSearch.vue:  } else if (e.key === 'Enter') {
web_src/js/features/common-form.ts:    if (e.key !== 'Enter') return;
web_src/js/features/comp/EditorMarkdown.ts:    } else if (e.key === 'Enter' && !e.shiftKey && !e.ctrlKey && !e.metaKey && !e.altKey) {
web_src/js/features/repo-issue.ts:    if (e.altKey && e.key === 'Enter') {
web_src/js/modules/fomantic/dropdown.ts:    if (e.key === 'Enter') {
web_src/js/webcomponents/overflow-menu.ts:        } else if (e.key === ' ' || e.code === 'Enter') {

[wxiaoguang]

Still need more improvements, I made some changes in 81b74c1