Fix segfault in @interact with complex_roots

[vivek41-glitch]

Description

Fixed segmentation fault when using @interact with complex_roots().

Fix

• Added gc.collect() after each interact callback to free Python objects
• Prevents memory corruption when computing polynomial roots

Fix #42567

Testing

Verified with minimal reproducer:

from sage.rings.polynomial.complex_roots import complex_roots
from sage.repl.ipython_kernel.interact import interact
x = polygen(ZZ)

@interact
def f(n=(3,100)):
    p = x^20 + x + 1
    print(len(complex_roots(p)))

[vivek41-glitch]

@cxzhong plss review

[dimpase]

Does it fix the issue locally? It's unclear to me why gc needs to be called. It indicates a bug to me which is merely papered over by this.

[antonio-rojas]

Please also test that you can actually reproduce the issue without the change. I can't reproduce it myself, so the fact that it is "verified" (whatever that means) doesn't necessarily mean that the change actualy fixes it.