[UUM-137643] Fix compilation errors and warnings

[mfe]

Purpose of this PR

Ticket/Jira #: UUM-137643

Compilation errors in the console:
error CS0619: 'Object.GetInstanceID()' is obsolete: 'GetInstanceID is deprecated. Use GetEntityId instead.

Warnings:
Logs: C:\build\output\unity\com.unity.recorder\com.unity.recorder\Editor\Sources\BaseTextureRecorder.cs(167,92): warning CS0618: 'FindObjectsSortMode' is obsolete: 'FindObjectsSortMode has been deprecated. Use the FindObjectsByType overloads that do not take a FindObjectsSortMode parameter.' (C:\build\output\unity\com.unity.recorder\com.unity.recorder\Editor\Sources\BaseTextureRecorder.cs:167)

Also replaced renderPipelineAsset by defaultRenderPipeline.

Testing

Functional Testing status:

Performance Testing status:

Overall Product Risks

Complexity:

Halo Effect:

Documentation & UX Writing

User facing text to review		Details
User interface
Public API docs
Changelog

Documentation halo effect		Jira link
User manual
Other docs

Additional information

Note to reviewers:

Reminder:

• Add entry in CHANGELOG.md
• check defaultRenderPipeline availability (2019 ?)
• Wait for Recorder 5.1.6 to be released (see UUM-137641 - Cf Recorder tests