mobile: fall back to mtime rather than ctime when no EXIF date is present

[Atemu]

The bug

~~Luckily, I was still testing things out but when I added other local albums on my phone, the photos' dates weren't their mtime or exif dates but the mtime of the directory containing the photos.~~

Edit: Far more detailed pdate below.

The OS that Immich Server is running on

NixOS

Version of Immich Server

v1.94.1

Version of Immich Mobile App

v1.94.1

Platform with the issue

• [ ] Server
• [ ] Web
• [X] Mobile

Your docker-compose.yml content

# Modified version of https://github.com/immich-app/immich/releases/download/v1.93.3/docker-compose.yml
version: "3.8"
name: immich
services:
  immich-server:
    container_name: immich_server
    image: ghcr.io/immich-app/immich-server:${IMMICH_VERSION:-release}
    command: ["start.sh", "immich"]
    volumes:
      - ${UPLOAD_LOCATION}:/usr/src/app/upload
      - /etc/localtime:/etc/localtime:ro
    env_file:
      - .env
    ports:
      - 2283:3001
    depends_on:
      - redis
      - database
    restart: 'no'
    logging:
      driver: json-file
  immich-microservices:
    container_name: immich_microservices
    image: ghcr.io/immich-app/immich-server:${IMMICH_VERSION:-release}
    command: ["start.sh", "microservices"]
    volumes:
      - ${UPLOAD_LOCATION}:/usr/src/app/upload
      - /etc/localtime:/etc/localtime:ro
    env_file:
      - .env
    depends_on:
      - redis
      - database
    restart: 'no'
    logging:
      driver: json-file
  immich-machine-learning:
    container_name: immich_machine_learning
    image: ghcr.io/immich-app/immich-machine-learning:${IMMICH_VERSION:-release}
    volumes:
      - model-cache:/cache
    env_file:
      - .env
    restart: 'no'
    logging:
      driver: json-file
  redis:
    container_name: immich_redis
    image: redis:6.2-alpine@sha256:c5a607fb6e1bb15d32bbcf14db22787d19e428d59e31a5da67511b49bb0f1ccc
    restart: 'no'
    logging:
      driver: json-file
  database:
    container_name: immich_postgres
    image: tensorchord/pgvecto-rs:pg14-v0.1.11@sha256:0335a1a22f8c5dd1b697f14f079934f5152eaaa216c09b61e293be285491f8ee
    env_file:
      - .env
    environment:
      POSTGRES_PASSWORD: ${DB_PASSWORD}
      POSTGRES_USER: ${DB_USERNAME}
      POSTGRES_DB: ${DB_DATABASE_NAME}
    volumes:
      - pgdata:/var/lib/postgresql/data
    restart: 'no'
    logging:
      driver: json-file
volumes:
  pgdata: null
  model-cache: null

Your .env content

DB_DATABASE_NAME=immich
DB_HOSTNAME=immich_postgres
DB_PASSWORD=postgres
DB_USERNAME=postgres
IMMICH_VERSION=release
REDIS_HOSTNAME=immich_redis
UPLOAD_LOCATION=/var/lib/immich/

Reproduction steps

(Not sure if 1-3 matter but I added them for completeness sake; it's all I did with the app.)

1. Have existing photos uploaded from PC
2. Add local album which contains these photos too
3. Wait for sync
4. Add a few other albums with photos from varying dates
5. Let it sync
6. Photos of the other albums all have the same date

Additional information

I first thought it was the mtime of the newest file in the directory but it was the same date for multiple local albums; the date I restored a backup on my phone.