fix: remove add to library button if already in library

[Kinsteen]

Description

Title is quite explanatory

Fixes #2459

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.
Provide instructions so we can reproduce.

• locally

[github-actions]

Pylint result on modfied files:

------------- Module bottles.backend.managers.library
bottles/backend/managers/library.py:124:0: C0303: Trailing whitespace (trailing-whitespace)
bottles/backend/managers/library.py:59:0: W1405: Quote delimiter " is inconsistent with the rest of the file (inconsistent-quotes)
bottles/backend/managers/library.py:75:0: W1405: Quote delimiter " is inconsistent with the rest of the file (inconsistent-quotes)
bottles/backend/managers/library.py:51:17: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bottles/backend/managers/library.py:58:15: C0103: Variable name "v" doesn't conform to snake_case naming style (invalid-name)
bottles/backend/managers/library.py:81:33: W0621: Redefining name 'uuid' from outer scope (line 19) (redefined-outer-name)
bottles/backend/managers/library.py:83:86: E0602: Undefined variable '_uuid' (undefined-variable)
bottles/backend/managers/library.py:101:15: C0103: Variable name "v" doesn't conform to snake_case naming style (invalid-name)
bottles/backend/managers/library.py:101:12: W0612: Unused variable 'k' (unused-variable)
bottles/backend/managers/library.py:122:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bottles/backend/managers/library.py:21:0: C0411: standard import "from pathlib import Path" should be placed before "from bottles.backend.utils import yaml" (wrong-import-order)
bottles/backend/managers/library.py:30:0: W0612: Unused variable 'LibraryManager' (unused-variable)
bottles/backend/managers/library.py:21:0: W0612: Unused variable 'Path' (unused-variable)
bottles/backend/managers/library.py:21:0: W0611: Unused Path imported from pathlib (unused-import)
------------- Module bottles.frontend.widgets.program
bottles/frontend/widgets/program.py:19:0: E0401: Unable to import 'gi.repository' (import-error)
bottles/frontend/widgets/program.py:60:4: R0913: Too many arguments (6/5) (too-many-arguments)
bottles/frontend/widgets/program.py:74:16: C0103: Variable name "w" doesn't conform to snake_case naming style (invalid-name)
bottles/frontend/widgets/program.py:105:12: C0103: Variable name "p" doesn't conform to snake_case naming style (invalid-name)
bottles/frontend/widgets/program.py:109:8: W0105: String statement has no effect (pointless-string-statement)
bottles/frontend/widgets/program.py:176:31: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:182:31: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:186:31: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:205:14: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:207:18: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:233:31: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:258:16: W0212: Access to a protected member __library of a client class (protected-access)
bottles/frontend/widgets/program.py:263:39: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:285:35: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:301:35: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:319:39: E0602: Undefined variable '_' (undefined-variable)
bottles/frontend/widgets/program.py:258:16: W0238: Unused private member `ProgramEntry.__library` (unused-private-member)
bottles/frontend/widgets/program.py:37:0: W0612: Unused variable 'ProgramEntry' (unused-variable)

Your code has been rated at 6.93/10

[TheEvilSkeleton]

The only problem I've encountered is that the "Add to Library" button is still present until you go back and reopen the bottle. It should be gone right after it is done adding to the library.

Marking as draft to make it clear that it's not ready to merge.