Add indicator for delisted mods

[Marioalexsan]

Closes #1988.

Implements a delist indicator for installed mods. A mod is considered as delisted if its install type is "managed", and a corresponding Thunderstore entry was not found for the installed mod. This likely means that the mod has either been rejected, or was delisted completely from Thunderstore.

This is an example of how it would look like with mods from the Atlyss community:

• BepInExPack, AppearancePlus by Nuilescent, CodeTalker by Robyn and EasySettings by Nessie are managed installs
• AppearancePlus is present in Thunderstore, but deprecated, so it shows up using its usual Deprecated tag
• CodeTalker has been delisted from Thunderstore, so it shows up using the new Delisted tag

Delisted packages that are locally installed remain untagged, meaning an equivalent local install of CodeTalker would remain unaffected.

[ebkr]

Have you tested this with a locally installed package? There isn't a case (that I can immediately see) where "managed" is never not the install mode.

[Marioalexsan]

Have you tested this with a locally installed package? There isn't a case (that I can immediately see) where "managed" is never not the install mode.

Locally installed packages are exactly when it's not a "managed" install, the corresponding field is an empty string. For example, this is my mods.yml for a profile containing BepInEx, a local mod that's not published anywhere at the moment, and an online mod:

- manifestVersion: 1
  name: BepInEx-BepInExPack
  authorName: BepInEx
  websiteUrl: https://thunderstore.io/c/atlyss/p/BepInEx/BepInExPack/
  displayName: BepInExPack
  description: BepInEx pack for Mono Unity games. Preconfigured and ready to use.
  gameVersion: '0'
  networkMode: both
  packageType: other
  installMode: managed
  installedAtTime: 1771807259017
  loaders: []
  dependencies: []
  incompatibilities: []
  optionalDependencies: []
  versionNumber:
    major: 5
    minor: 4
    patch: 2304
  enabled: true
- manifestVersion: 1
  name: Marioalexsan-PerformanceMetrics
  authorName: Marioalexsan
  websiteUrl: ''
  displayName: PerformanceMetrics
  description: Displays Unity's performance metrics in-game (memory, CPU usage, etc.)
  gameVersion: ''
  networkMode: ''
  packageType: ''
  installMode: ''
  installedAtTime: 1771964207261
  loaders: []
  dependencies:
    - BepInEx-BepInExPack-5.4.2100
  incompatibilities: []
  optionalDependencies: []
  versionNumber:
    major: 1
    minor: 0
    patch: 0
  enabled: true
- manifestVersion: 1
  name: AtlyssModding-Atlyss_UnityExplorer
  authorName: AtlyssModding
  websiteUrl: https://thunderstore.io/c/atlyss/p/AtlyssModding/Atlyss_UnityExplorer/
  displayName: Atlyss_UnityExplorer
  description: >-
    A fork of Yukieiji's UnityExplorer fork, made to work with ATLYSS's beta
    branch (Unity 6)
  gameVersion: '0'
  networkMode: both
  packageType: other
  installMode: managed
  installedAtTime: 1771964324345
  loaders: []
  dependencies:
    - BepInEx-BepInExPack-5.4.2304
  incompatibilities: []
  optionalDependencies: []
  versionNumber:
    major: 4
    minor: 13
    patch: 100
  enabled: true

[Marioalexsan]

So that explicit check for the "managed" install type is supposed to handle local mod installs by not showing any messages for them. The logic is that local mod installs are either development versions, unpublished mods, or otherwise wouldn't benefit from the "Delisted" notification.