To solve the given optimization problem, we first need to convert the natural language description into a symbolic representation. This involves defining variables for the quantities we want to optimize and translating the constraints and objective function into algebraic terms.

Let's define the following symbolic variables:
- $x_1$: The number of Combo 1 deals sold.
- $x_2$: The number of Combo 2 deals sold.

The objective function, which represents the total profit, can be written as:
\[4x_1 + 4.5x_2\]

This is because each Combo 1 deal yields a profit of $4 and each Combo 2 deal yields a profit of $4.50.

Next, we need to define the constraints based on the available quantities of gummy bears, gummy worms, and sour candies:
1. Gummy Bears: $25x_1 + 12x_2 \leq 1200$
2. Gummy Worms: $20x_1 + 21x_2 \leq 1400$
3. Sour Candies: $15x_1 + 24x_2 \leq 900$

Additionally, since we cannot sell a negative number of combos, we have non-negativity constraints:
- $x_1 \geq 0$
- $x_2 \geq 0$

Now, let's represent the problem symbolically as requested:

```json
{
    'sym_variables': [('x1', 'Number of Combo 1 deals'), ('x2', 'Number of Combo 2 deals')],
    'objective_function': '4*x1 + 4.5*x2',
    'constraints': [
        '25*x1 + 12*x2 <= 1200',
        '20*x1 + 21*x2 <= 1400',
        '15*x1 + 24*x2 <= 900',
        'x1 >= 0',
        'x2 >= 0'
    ]
}
```

To solve this problem using Gurobi in Python, we'll write the following code:

```python
from gurobipy import *

# Create a model
m = Model("Grocery_Store_Optimization")

# Define variables
x1 = m.addVar(name="Combo_1", vtype=GRB.CONTINUOUS, lb=0)
x2 = m.addVar(name="Combo_2", vtype=GRB.CONTINUOUS, lb=0)

# Set objective function
m.setObjective(4*x1 + 4.5*x2, GRB.MAXIMIZE)

# Add constraints
m.addConstr(25*x1 + 12*x2 <= 1200, name="Gummy_Bears_Constraint")
m.addConstr(20*x1 + 21*x2 <= 1400, name="Gummy_Worms_Constraint")
m.addConstr(15*x1 + 24*x2 <= 900, name="Sour_Candies_Constraint")

# Optimize model
m.optimize()

# Print results
if m.status == GRB.OPTIMAL:
    print("Optimal solution found:")
    print(f"Combo 1: {x1.x}")
    print(f"Combo 2: {x2.x}")
    print(f"Total Profit: ${4*x1.x + 4.5*x2.x:.2f}")
else:
    print("No optimal solution found.")
```