Delete retention policy not working as expected

### Which service(blob, file, queue, table) does this issue concern?
blob
### Which version of the Azurite was used?
3.2.0-preview
### Where do you get Azurite? (npm, DockerHub, NuGet, Visual Studio Code Extension)
npm
### What's the Node.js version?
v10.16.3
### What problem was encountered?
as titled
### Steps to reproduce the issue?
1. Configure delete retention policy api to enable soft delete (200 OK)
2. Delete a blob (200 OK)
3. List blob including deleted ones
4. The deleted blob isn't there
### Have you found a mitigation/solution?
Nope

Here are the requests I used to reproduce the issue:
configure:
```
PUT http://127.0.0.1:10000/devstoreaccount1/?comp=properties&restype=service HTTP/1.1
content-type: application/xml;charset="utf-8"
content-length: 176
x-ms-client-request-id: adae2790-6257-11ea-beaa-b72d28d2bc0b
user-agent: Microsoft Azure Storage Explorer, 1.12.0, win32, Azure-Storage/2.10.3 (NODE-VERSION v10.11.0; Windows_NT 10.0.18363)
x-ms-version: 2018-03-28
x-ms-date: Mon, 09 Mar 2020 22:45:30 GMT
accept: application/atom+xml,application/xml
Accept-Charset: UTF-8
authorization: SharedKey devstoreaccount1:yEwi66GPeI19sNt0/Rf9wAQcJMu5cGR/2lONyfSacp4=
host: 127.0.0.1:10000
Connection: keep-alive

true30
```
delete:
```
DELETE http://127.0.0.1:10000/devstoreaccount1/test1/fc075edd-07d7-9144-4efb-941252e69025--00000.steV10 HTTP/1.1
x-ms-client-request-id: f4b649e0-6259-11ea-add5-759c990ca7f3
user-agent: Microsoft Azure Storage Explorer, 1.12.0, win32, Azure-Storage/2.10.3 (NODE-VERSION v10.11.0; Windows_NT 10.0.18363)
x-ms-version: 2018-03-28
x-ms-date: Mon, 09 Mar 2020 23:01:48 GMT
accept: application/atom+xml,application/xml
Accept-Charset: UTF-8
content-type:
content-length: 0
authorization: SharedKey devstoreaccount1:QUF3Y6eupU8y4kH9LTScrC43LXd7uL0DmTpghK6JHuc=
host: 127.0.0.1:10000
Connection: keep-alive
```