[Improvement]: Simplify the package locking mode deriving logic

[gayaldassanayake]

Description

The package locking mode resolution has been distributed among different classes during the package resolution. While this works without any issues, it's a bit confusing. It impacts the readability and the maintainability of the code base.

Describe your problem(s)

In PackageResolution.java, the locking mode resolution logic is as follows.

if dependencies toml exists
    if new distribution version
        locking_mode = SOFT
    else
        locking_mode = MEDIUM
else # fresh project
    if sticky
        locking_mode = MEDIUM
    else 
        locking_mode = SOFT

However, in io.ballerina.projects.internal.ResolutionEngine#resolveDirectDependencies and io.ballerina.projects.internal.ResolutionEngine#getRequestForUnresolvedNode, we have added an additional check to check if sticky flag is on.

locking_mode = sticky? HARD: resolutionOptions.packageLockingMode();

Describe your solution(s)

Instead, we can unify this to be in PackageResolution as follows.

if dependencies toml exists
    if sticky
        locking_mode = HARD
    else if new distribution version
        locking_mode = SOFT
    else
        locking_mode = MEDIUM
else # fresh project
    if sticky
        locking_mode = MEDIUM
    else 
        locking_mode = SOFT

Related area

-> Compilation

Related issue(s) (optional)

No response

Suggested label(s) (optional)

No response

Suggested assignee(s) (optional)

No response