fix(EnglishCpVPhonemizer): assign this.singer before ReadDictionaryAndInit

[yaaayaaa]

Problem

EnglishCpVPhonemizer.SetSinger() calls ReadDictionaryAndInit() before
assigning this.singer. ReadDictionaryAndInit() loads the base dictionary
which references singer.Found — a NullReferenceException is thrown,
caught silently inside ReadDictionary, leaving dict null.

Subsequent Process() calls then return a single empty-string phoneme
for every input.

Repro

Build OpenUtau.Test and run:

var phonemizer = new EnglishCpVPhonemizer();
phonemizer.SetSinger(anyLoadedSinger);  // dict stays null
var result = phonemizer.Process(note, ...);  // returns [""]

Fix

Swap the two lines in SetSinger so this.singer is set before init.

Impact

Makes EnglishCpVPhonemizer actually work in headless test environments
and any scenario where ReadDictionaryAndInit runs before a real Process.

Discovered during conformance testing against an en_liee voicebank.
Prior to this fix, tests had to use a reflection workaround to set
this.singer before invoking SetSinger.