#332: fixes inconsistency in the incr command

[Maveric-k07]

fixes #332

Inconsistencies found only with the error messages and not in functionality.

1. Data types:
   Redis: "INCR strkey": "Error: value is not an integer or out of range"
   DiceDB: "INCR strkey": "Error: the operation is not permitted on this encoding"

   Redis: "INCR floatkey": "Error: value is not an integer or out of range"
   DiceDB: "INCR floatkey": "Error: the operation is not permitted on this encoding"

   This is the case for all non-integer values.

   The error messages are different, though the behavior (not incrementing non-integer values) is consistent.

2. Overflow handling:
   Redis: "INCR maxint": "Error: increment or decrement would overflow"
   DiceDB: "INCR maxint": "Error: value is out of range"

   The error messages differ, but both prevent overflow.

Cases working correctly:

1. Basic functionality (INCR and GET)
2. Incrementing large integers within range, integer string value
3. Negative numbers handling
4. Zero handling
5. Large increments
6. Key naming (empty string and colon-separated keys)
7. Multiple increments
8. INCR and DEL interaction
9. INCR and RENAME
10. INCR and COPY

To test with keys that have expiry I had to run the following:

"INCR with EXPIRE": [
        "SET expirablekey 10",
        "EXPIRE expirablekey 60",
        "INCR expirablekey",
        "TTL expirablekey"
]

This can be achieved by using SETEX. Could be a good addition.
Another good to have will be the FLUSHALL command.
edit: saw that there is already progress on SETEX command - will be a good addition.

cc: @JyotinderSingh Apologies for the delay in creating the PR;

[JyotinderSingh]

Thanks for these fixes @Maveric-k07! The changes look good. Approved