Parse real number literals as the Decimal type

### Is your feature request related to a problem or challenge?

During the fix for [12655](https://github.com/apache/datafusion/issues/12655), I found that the root cause was that we parse real number literals as `f64`. When performing coercion between `f32` and `f64`, it can lead to significant precision problems.

As a solution, I proposed changing the default behavior to parse real number literals as Decimal. This not only helps avoid the precision issues between f32 and f64, but also aligns the default behavior with `Postgres` and `DuckDB`.

## Postgres
```
SELECT 1.3 as real , pg_typeof(1.3) as type;
```
| real | type |
|------|---------|
| 1.3 | numeric |

## DuckDB
```
SELECT 1.3 as real , typeof(1.3) as type;
```
| real | type |
|------|---------------|
| 1.3 | DECIMAL(2,1) |

### DataFusion
```
SELECT 1.3 as real , arrow_typeof(1.3) as type;
```
| real | type |
|------|---------|
| 1.3 | Float64 |

Fortunately, we have excellent support for Decimal, so the only change we need to make is setting the default value of `sql_parser.parse_float_as_decimal` to true. However, I believe this change could be breaking, as it alters the current behavior.

Therefore, it would be important to get broader community consensus before proceeding.

cc @alamb @jayzhan211 @jonahgao

### Describe the solution you'd like

change `sql_parser.parse_float_as_decimal` to `true`

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by locating the sql_parser.parse_float_as_decimal setting and inspect how real-number literals are currently typed and tested. Compare the behavior with the PostgreSQL and DuckDB examples; done means the default produces Decimal values without regressing supported parsing or coercion behavior.

Written by the indexing model from the issue text.