fix: avoid integer abs in MatrixTransferStatic.cc and calorimetry_HEXPLIT.cc

[wdconinc]

Briefly, what does this PR introduce?

abs without std results in using integer absolute value, which the compiler warns about:

warning: using integer absolute value function 'abs' when argument is of floating point type [-Wabsolute-value]

What kind of change does this PR introduce?

• Bug fix (issue #__)
• New feature (issue #__)
• Documentation update
• Other: __

Please check if this PR fulfills the following:

• Tests for the changes have been added
• Documentation has been added / updated
• Changes have been communicated to collaborators

Does this PR introduce breaking changes? What changes might users need to make to their code?

No.

Does this PR change default behavior?

No.

[github-actions]

Capybara summary for PR 1703

• rec_dis_10x100_minQ2=0_craterlake
• rec_dis_10x100_minQ2=1000_craterlake_tracking_only
• rec_dis_18x275_minQ2=0_craterlake_18x275
• rec_dis_18x275_minQ2=1000_craterlake_18x275
• rec_dis_5x41_minQ2=0_craterlake_5x41
• rec_e_1GeV_20GeV_craterlake
• rec_pi_1GeV_20GeV_craterlake
  ^{_{Last updated 2025-01-15T13:33-05:00 0f7457a}}