Add `If` task

[superstar54]

Using the If Task

In the WorkGraph user interface, the If Task is visually represented as an "If Zone." This zone encapsulates all its child tasks, which are executed based on the defined conditions.

• Conditions: The If Zone includes a conditions socket, which determines when the tasks inside the zone should be executed.
• Invert_condition: If this input is True, it will invert the conditions.
• Task Linking: Tasks located outside the If Zone can be directly linked to tasks within the zone, allowing for dynamic workflow adjustments based on conditional outcomes.

Example

if2 = wg.add_task("If", name="if_false",
                        conditions=condition1.outputs["result"],
                        invert_condition=True)
if2.children.append("multiply1")

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 98.43750% with 1 line in your changes missing coverage. Please review.

Project coverage is 76.56%. Comparing base (5937b88) to head (b1845ce). Report is 23 commits behind head on main.

Files	Patch %	Lines
tests/test_if.py	95.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #222 +/- ## ========================================== + Coverage 75.75% 76.56% +0.80% ========================================== Files 70 71 +1 Lines 4615 5039 +424 ========================================== + Hits 3496 3858 +362 - Misses 1119 1181 +62 ``` | [Flag](https://app.codecov.io/gh/aiidateam/aiida-workgraph/pull/222/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam) | Coverage Δ | | |---|---|---| | [python-3.11](https://app.codecov.io/gh/aiidateam/aiida-workgraph/pull/222/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam) | `76.56% <98.43%> (+0.89%)` | :arrow_up: | | [python-3.9](https://app.codecov.io/gh/aiidateam/aiida-workgraph/pull/222/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam) | `?` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidateam#carryforward-flags-in-the-pull-request-comment) to find out more.

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