Subgraphs with `_type` fail at auto-select

[0xMochan]

Describe the bug
With Subgrounds feature of auto select when given a top-level field or entity, it automatically grabs every scalar field + every object field's id. This will clash causing non-sense errors if a subgraph has a rare _type or other variable that exists on the FieldPath object.

To Reproduce
Steps to reproduce the behavior:

1. Test out this snippet of code with the latest subgrounds

from subgrounds import Subgrounds

sg = Subgrounds()
aave_v2 = sg.load_subgraph("https://api.thegraph.com/subgraphs/name/messari/aave-v2-ethereum")
sg.query_df(aave_v2.Query.markets)

2. Observe an absurd stack limit error dealing with crazy recursion.

Expected behavior
There should be no clash and the data should be accessed

Python version (please complete the following information):

• Python 3.11 w/ Subgrounds 1.6.0

Additional context
Potential Solutions:
a) we rename all internal variables of FieldPath (and Subgraph) to start with __ to enable python's name-mangling
b) we replace __getattribute__ with __getattr__ so that internal vars don't go thru a special access layer

• this would enforce the use of ._select if there was a name clash with a field

Doing both a) and b) could be ideal since the name-mangle will reduce collisions and the __getattr__ would ensure consistent and crashless behavior in edge cases.

Likely, the hardest part to fixing this issue is fixing all of the test cases as well.