Subgraphs with `_type` fail at auto-select

**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
```py
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.