[3.x] Fix Tween.is_active() always true after stop() and then start() (Fix #39760 & #39801)

[jmb462]

Fix #39760 & #39801 for 3.2 branch

These issues were fixed in 4.0 master branch (and closed) but are still active in the 3.2 branch.

Issues :

• Tween always active after stop() and (re) start() Tween.is_active() always true after tween.stop() and then tween.start() #39760
• Tween never repeat after stop() and (re) start() even if repeat is true bug with Tween.is_active, fixes #39760 #39801 (this issue is a consequence from the previous)

Cause :

When a tween was stopped, each interpolation in the list was set to active=false
then, the main active bool was set to false.

When starting the tween again, the main active bool was set to true but not each interpolation in the list : so no repeat was happening.

Fix proposal : (Backport from my previous merged PR #46609 for 4.0)

I've added a for loop to reactivate each interpolation in the interpolates list when start() is called.
Need to seek to 0.0 too (only if tween has been stopped by stop_all()) because we don't want start() to act as resume() after stop_all().

[akien-mga]

I wouldn't merge at this stage for 3.3 (too close to the stable release so too risky), but we can merge for 3.4, and cherry-pick for 3.3.1.

[akien-mga]

Thanks!

[akien-mga]

I prefer not to cherry-pick for 3.3 at this stage.