WorldEnvironment's high-quality glow mode doesn't work as expected

[Calinou]

Godot version

3.4.rc (a05aefb)

System information

Fedora 34, GeForce GTX 1080 (NVIDIA 470.74)

Issue description

The high-quality glow mode backported to 3.x by #51491 doesn't work as expected in both GLES3 and GLES2.

GLES3

Low quality

Glow width depends on rotation, as expected.

gles3-low-quality.mp4

High quality

Glow width depends on rotation, but it shouldn't in this mode.

gles3-high-quality.mp4

GLES2

Low quality

Glow width depends on rotation, as expected.

gles2-low-quality.mp4

High quality

Glow width depends on rotation, but it shouldn't in this mode.

gles2-high-quality.mp4

Steps to reproduce

• Create a long and thin object with high emission value.
• Enable Glow in WorldEnvironment. Unzoom to make the object small in the viewport, and rotate the camera. Notice the glow width changing depending on camera rotation.
• Enable Glow > High Quality in WorldEnvironment. Unzoom to make the object small in the viewport, and rotate the camera. Notice the glow width still changing depending on camera rotation, even though it shouldn't when high-quality glow is used.

Minimal reproduction project

glow_orientation_issue.zip (MRP by fracteed)